diff --git a/.gitignore b/.gitignore
index 595184e..e0e6fff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,7 +6,6 @@
 !.gitignore
 !codecov.yml
 !skeleton.html
-!**/xmake.lua
 !**/meson.build
 !**/*.wrap
 !meson_options.txt
diff --git a/compile_wasm.py b/compile_wasm.py
index 3bd1afd..7214801 100644
--- a/compile_wasm.py
+++ b/compile_wasm.py
@@ -13,7 +13,7 @@ def compile(sources, output):
                     if file_extension == '.d' and filename != 'package':
                         files.append(os.path.join(r, file))
 
-    ldc_cmd = 'ldc2 ' + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-unknown-wasm -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
+    ldc_cmd = 'ldc2 ' + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-emscripten -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
 
     for path in sources:
         ldc_cmd += '-I' + path + ' '
@@ -33,7 +33,7 @@ def compile(sources, output):
 shared_flags = ''
 clean = 0
 emc_flags = ''
-ldc_flags = '--d-version=ECSEmscripten '
+ldc_flags = ''
 import_paths = ['source','tests']
 build_tests = 0
 
diff --git a/demos/compile_wasm.py b/demos/compile_wasm.py
index 06d31ac..b178260 100644
--- a/demos/compile_wasm.py
+++ b/demos/compile_wasm.py
@@ -1,7 +1,6 @@
 import os
 import ntpath
 import sys
-import imp
 
 def compile(sources, output):
     files = []
@@ -14,7 +13,7 @@ def compile(sources, output):
                     if file_extension == '.d' and filename != 'package':
                         files.append(os.path.join(r, file))
 
-    ldc_cmd = compiler + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-unknown-wasm -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
+    ldc_cmd = compiler + shared_flags + ldc_flags + '-oq -mtriple=wasm32-unknown-emscripten -betterC --output-bc --od=.bc --singleobj --checkaction=C --of=' + output + ' '
 
     for path in sources:
         ldc_cmd += '-I' + path + ' '
@@ -41,7 +40,7 @@ only_bc = 0
 multi = 0
 sources = ['tests', 'source']
 emc_flags = '-s USE_SDL=2 -s USE_SDL_IMAGE=2 -s SDL2_IMAGE_FORMATS="[\'png\']" '
-ldc_flags = '--d-version=ECSEmscripten --d-version=SDL_209 --d-version=BindSDL_Static --d-version=BindSDL_Image --d-version=MM_USE_POSIX_THREADS '
+ldc_flags = '--d-version=SDL_209 --d-version=BindSDL_Static --d-version=BindSDL_Image --d-version=MM_USE_POSIX_THREADS '
 import_paths = ['external/sources', 'external/imports', 'external/wasm_imports', '../source', 'utils/source', 'simple/source']
 
 for arg in sys.argv[1:]:
@@ -121,8 +120,9 @@ emcc_cmd += 'demo.bc '
 
 os.system("mkdir build")
 
-emscripten = imp.load_source('', os.path.expanduser("~") + '/.emscripten')
-pack_cmd = emscripten.EMSCRIPTEN_ROOT + '/tools/file_packager.py build/assets.data --preload assets --js-output=build/assets.js'
+# emscripten = imp.load_source('', os.path.expanduser("~") + '/.emscripten')
+# pack_cmd = emscripten.EMSCRIPTEN_ROOT + '/tools/file_packager.py build/assets.data --preload assets --js-output=build/assets.js'
+pack_cmd = os.path.expandvars('$EMSDK/upstream/emscripten') + '/tools/file_packager.py build/assets.data --preload assets --js-output=build/assets.js'
 print('Packafing files: ' + pack_cmd)
 
 os.system(pack_cmd)
diff --git a/dub.json b/dub.json
index 117c762..602117d 100755
--- a/dub.json
+++ b/dub.json
@@ -7,9 +7,9 @@
 	"description": "Dynamic Entity Component System",
 	"copyright": "Copyright © 2018-2023, Michał Masiukiewicz, Dawid Masiukiewicz",
 	"license": "BSD 3-clause",
-	"sourcePaths" : ["source/"],
+	"sourcePaths" : ["source\/"],
 	"excludedSourceFiles":[
-		"source/ecs/traits.d"
+		"source\/ecs\/traits.d"
 	],
 	"configurations" : [
 		{
@@ -21,7 +21,7 @@
 			"sourceFiles" : ["tests/tests.d"],
 			"targetType" : "executable",
 			"excludedSourceFiles":[
-				"source/win_dll.d"
+				"source\/win_dll.d"
 			]
 		},
 		{
@@ -45,7 +45,7 @@
 			"sourcePaths": ["source/","tests/"],
 			"mainSourceFile":"tests/runner.d",
 			"excludedSourceFiles":[
-				"source/win_dll.d",
+				"source\/win_dll.d",
 				"tests/tests.d"
 			],
 			"dflags": [
@@ -58,7 +58,7 @@
 			"sourcePaths": ["source/","tests/"],
 			"mainSourceFile":"tests/runner.d",
 			"excludedSourceFiles":[
-				"source/win_dll.d",
+				"source\/win_dll.d",
 				"tests/tests.d"
 			],
 			"dflags": [
@@ -70,7 +70,7 @@
 			"name" : "library-betterC",
 			"targetType" : "library",
 			"excludedSourceFiles":[
-				"source/win_dll.d"
+				"source\/win_dll.d"
 			],
 			"dflags": [
 				"-betterC",
@@ -101,7 +101,7 @@
 			"targetType" : "executable",
 			"sourceFiles" : ["tests/tests.d"],
 			"excludedSourceFiles":[
-				"source/win_dll.d"
+				"source\/win_dll.d"
 			],
 			"dflags": [
 				"-betterC"
@@ -125,7 +125,7 @@
 			"sourcePaths": ["source/","tests/"],
 			"mainSourceFile":"tests/runner.d",
 			"excludedSourceFiles":[
-				"source/win_dll.d",
+				"source\/win_dll.d",
 				"tests/tests.d"
 			]
 		}
diff --git a/meson.build b/meson.build
index 3f261f8..141cb25 100644
--- a/meson.build
+++ b/meson.build
@@ -58,7 +58,7 @@ threads_dep = dependency('threads')
 d_versions = []
 deps = []
 if host_machine.cpu_family() == 'wasm32'
-	d_versions += 'ECSEmscripten'
+
 else
 	# meson incorectly adds "-s USE_PTHREADS=1" to ldc2 invocation whe pthreads is added as dependency
 	# add it for non wasm builds
diff --git a/source/bubel/ecs/atomic.d b/source/bubel/ecs/atomic.d
index 40f0aa9..d8995ae 100644
--- a/source/bubel/ecs/atomic.d
+++ b/source/bubel/ecs/atomic.d
@@ -9,124 +9,5 @@ License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.atomic;
 
-version (Emscripten) version = ECSEmscripten;
+public import core.atomic;
 
-version (ECSEmscripten)
-{
-    import std.traits;
-
-    enum MemoryOrder
-    {
-        acq,
-        acq_rel,
-        raw,
-        rel,
-        seq
-    }
-
-    extern (C) ubyte emscripten_atomic_cas_u8(void* addr, ubyte oldVal, ubyte newVal) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_cas_u16(void* addr, ushort oldVal, ushort newVal) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_cas_u32(void* addr, uint oldVal, uint newVal) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_load_u8(const void* addr) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_load_u16(const void* addr) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_load_u32(const void* addr) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_store_u8(void* addr, ubyte val) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_store_u16(void* addr, ushort val) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_store_u32(void* addr, uint val) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_add_u8(void* addr, ubyte val) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_add_u16(void* addr, ushort val) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_add_u32(void* addr, uint val) @nogc nothrow pure;
-
-    extern (C) ubyte emscripten_atomic_sub_u8(void* addr, ubyte val) @nogc nothrow pure;
-    extern (C) ushort emscripten_atomic_sub_u16(void* addr, ushort val) @nogc nothrow pure;
-    extern (C) uint emscripten_atomic_sub_u32(void* addr, uint val) @nogc nothrow pure;
-
-    public pure nothrow @nogc Unqual!T atomicOp(string op, T, V1)(ref shared T val, V1 mod)
-    {
-        static if (op == "+=")
-        {
-            static if (is(T == byte) || is(T == ubyte))
-                return cast(Unqual!T)(emscripten_atomic_add_u8(cast(void*)&val,
-                        cast(Unqual!T) mod) + 1);
-            else static if (is(T == short) || is(T == ushort))
-                return cast(Unqual!T)(emscripten_atomic_add_u16(cast(void*)&val,
-                        cast(Unqual!T) mod) + 1);
-            else static if (is(T == int) || is(T == uint))
-                return cast(Unqual!T)(emscripten_atomic_add_u32(cast(void*)&val,
-                        cast(Unqual!T) mod) + 1);
-            else
-                static assert(0);
-        }
-        else static if (op == "-=")
-        {
-            static if (is(T == byte) || is(T == ubyte))
-                return cast(Unqual!T)(emscripten_atomic_sub_u8(cast(void*)&val,
-                        cast(Unqual!T) mod) - 1);
-            else static if (is(T == short) || is(T == ushort))
-                return cast(Unqual!T)(emscripten_atomic_sub_u16(cast(void*)&val,
-                        cast(Unqual!T) mod) - 1);
-            else static if (is(T == int) || is(T == uint))
-                return cast(Unqual!T)(emscripten_atomic_sub_u32(cast(void*)&val,
-                        cast(Unqual!T) mod) - 1);
-            else
-                static assert(0);
-        }
-    }
-
-    public pure nothrow @nogc @trusted void atomicStore(MemoryOrder ms = MemoryOrder.seq, T, V)(ref T val,
-            V newval)
-    {
-        alias UT = Unqual!T;
-        static if (is(UT == bool) || is(UT == byte) || is(UT == ubyte))
-            emscripten_atomic_store_u8(cast(void*)&val, cast(UT) newval);
-        else static if (is(UT == short) || is(UT == ushort))
-            emscripten_atomic_store_u16(cast(void*)&val, cast(UT) newval);
-        else static if (is(UT == int) || is(UT == uint))
-            emscripten_atomic_store_u32(cast(void*)&val, cast(UT) newval);
-        else
-            static assert(0);
-    }
-
-    public pure nothrow @nogc @trusted T atomicLoad(MemoryOrder ms = MemoryOrder.seq, T)(
-            ref const T val)
-    {
-        alias UT = Unqual!T;
-        static if (is(UT == bool))
-            return emscripten_atomic_load_u8(cast(const void*)&val) != 0;
-        else static if (is(UT == byte) || is(UT == ubyte))
-            return emscripten_atomic_load_u8(cast(const void*)&val);
-        else static if (is(UT == short) || is(UT == ushort))
-            return emscripten_atomic_load_u16(cast(const void*)&val);
-        else static if (is(UT == int) || is(UT == uint))
-            return emscripten_atomic_load_u32(cast(const void*)&val);
-        else
-            static assert(0);
-    }
-
-    public pure nothrow @nogc @trusted bool cas(MemoryOrder succ = MemoryOrder.seq,
-            MemoryOrder fail = MemoryOrder.seq, T, V1, V2)(T* here, V1 ifThis, V2 writeThis)
-    {
-        alias UT = Unqual!T;
-        static if (is(UT == bool))
-            return emscripten_atomic_cas_u8(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else static if (is(UT == byte) || is(UT == ubyte))
-            return emscripten_atomic_cas_u8(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else static if (is(UT == short) || is(UT == ushort))
-            return emscripten_atomic_cas_u16(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else static if (is(UT == int) || is(UT == uint))
-            return emscripten_atomic_cas_u32(cast(void*) here,
-                    cast(Unqual!T) ifThis, cast(Unqual!T) writeThis) == ifThis;
-        else
-            static assert(0);
-    }
-}
-else
-{
-    public import core.atomic;
-}
diff --git a/source/bubel/ecs/entity.d b/source/bubel/ecs/entity.d
index d6b4ef8..76a8a2f 100644
--- a/source/bubel/ecs/entity.d
+++ b/source/bubel/ecs/entity.d
@@ -44,7 +44,7 @@ struct Entity
         return cast(T*)getComponent(becsID!T);
     }
 
-    void* getComponent(ushort component_id) const nothrow @nogc
+    export void* getComponent(ushort component_id) const
     {
         EntityManager.EntitiesBlock* block = gEntityManager.getMetaData(&this);
         EntityManager.EntityInfo* info = block.type_info;
@@ -54,7 +54,7 @@ struct Entity
         return (cast(void*)block + info.deltas[component_id] + block.entityIndex(&this) * gEntityManager.components[component_id].size);
     }
 
-    bool hasComponent(ushort component_id) const nothrow @nogc
+    export bool hasComponent(ushort component_id) const
     {
         EntityManager.EntitiesBlock* block = gEntityManager.getMetaData(&this);
         EntityManager.EntityInfo* info = block.type_info;
@@ -62,7 +62,7 @@ struct Entity
         return true;
     }
 
-    EntityMeta getMeta() const nothrow @nogc
+    export EntityMeta getMeta() const
     {
         EntityMeta meta;
         meta.block = gEntityManager.getMetaData(&this);
@@ -85,7 +85,7 @@ struct EntityMeta
         return cast(T*)getComponent(becsID!T);
     }
     
-    void* getComponent(ushort component_id) const nothrow @nogc
+    export void* getComponent(ushort component_id) const
     {
         const (EntityManager.EntityInfo)* info = block.type_info;
 
@@ -95,7 +95,7 @@ struct EntityMeta
         return (cast(void*)block + info.deltas[component_id] + index * gEntityManager.components[component_id].size);
     }
 
-    bool hasComponent(ushort component_id) const nothrow @nogc
+    export bool hasComponent(ushort component_id) const
     {
         const EntityManager.EntityInfo* info = block.type_info;
         if (component_id >= info.deltas.length || info.deltas[component_id] == 0)return false;
@@ -124,7 +124,7 @@ export struct EntityTemplate
     /************************************************************************************************************************
     Get specified component. If component doesn't exist function return null. Returned pointer is valid during EntityTemplate lifetime.
     */
-    T* getComponent(T)()
+    T* getComponent(T)() nothrow @nogc
     {
         if(becsID!T >= info.tmpl_deltas.length || info.tmpl_deltas[becsID!T] == ushort.max)return null;
         return cast(T*)(entity_data.ptr + info.tmpl_deltas[becsID!T]);
@@ -133,7 +133,7 @@ export struct EntityTemplate
     /************************************************************************************************************************
     Get specified component. If component doesn't exist function return null. Returned pointer is valid during EntityTemplate lifetime.
     */
-    void* getComponent(ushort component_id) const nothrow @nogc
+    export void* getComponent(ushort component_id) const nothrow @nogc
     {
         if(component_id >= info.tmpl_deltas.length || info.tmpl_deltas[component_id] == ushort.max)return null;
         return cast(void*)(entity_data.ptr + info.tmpl_deltas[component_id]);
diff --git a/source/bubel/ecs/hash_map.d b/source/bubel/ecs/hash_map.d
index 66a0756..7ba6137 100755
--- a/source/bubel/ecs/hash_map.d
+++ b/source/bubel/ecs/hash_map.d
@@ -28,7 +28,7 @@ export ulong defaultHashFunc(T)(auto ref T t) nothrow @nogc
 	}
 }
 
-ulong hash(byte[] array) nothrow @nogc
+export ulong hash(byte[] array) nothrow @nogc
 {
 	ulong hash = 0;
 
diff --git a/source/bubel/ecs/manager.d b/source/bubel/ecs/manager.d
index f1edf5c..b5220f4 100644
--- a/source/bubel/ecs/manager.d
+++ b/source/bubel/ecs/manager.d
@@ -27,6 +27,8 @@ alias SerializeVector = bubel.ecs.vector.Vector!ubyte;
 ///Global EntityManager used for everything.
 export __gshared EntityManager* gEntityManager = null;
 
+version(D_BetterC) version = NoDRuntime;
+
 /************************************************************************************************************************
 Entity manager is responsible for everything.
 
@@ -359,7 +361,7 @@ export struct EntityManager
     void registerSystem(Sys)(int priority, const(char)[] pass_name)
     {
         ushort pass = passes_map.get(pass_name, ushort.max);
-        version (D_BetterC)
+        version (NoDRuntime)
             assert(pass != ushort.max, "Update pass doesn't exist.");
         else
             assert(pass != ushort.max, "Update pass (Name " ~ pass_name ~ ") doesn't exist.");
@@ -381,7 +383,7 @@ export struct EntityManager
 
         assert(register_state,
             "registerSystem must be called between beginRegister() and endRegister().");
-        version (D_BetterC)
+        version (NoDRuntime)
             assert(pass < passes.length, "Update pass doesn't exist.");
         else
             assert(pass < passes.length, "Update pass (ID " ~ pass.to!string ~ ") doesn't exist.");
@@ -390,7 +392,7 @@ export struct EntityManager
         enum SystemName = fullName!Sys;
         //enum SystemName = Sys.stringof;
 
-        System system;
+        System system = System();
         system.m_pass = pass;
 
         // static if (!(hasMember!(Sys, "system_id")) || !is(typeof(Sys.system_id) == ushort))
@@ -840,7 +842,7 @@ export struct EntityManager
             foreach (iii, comp_info; components_info.req)
             {
                 ushort comp = components_map.get(cast(char[]) comp_info.type, ushort.max);
-                version (D_BetterC)
+                version (NoDRuntime)
                     assert(comp != ushort.max,
                         "Can't register system \"" ~ SystemName
                             ~ "\" due to non existing component.");
@@ -852,7 +854,7 @@ export struct EntityManager
             foreach (iii, comp_info; components_info.excluded)
             {
                 ushort comp = components_map.get(cast(char[]) comp_info.type, ushort.max);
-                version (D_BetterC)
+                version (NoDRuntime)
                     assert(comp != ushort.max,
                         "Can't register system \"" ~ SystemName
                             ~ "\" due to non existing component.");
@@ -864,7 +866,7 @@ export struct EntityManager
             foreach (iii, comp_info; components_info.optional)
             {
                 ushort comp = components_map.get(cast(char[]) comp_info.type, ushort.max);
-                version (D_BetterC)
+                version (NoDRuntime)
                     assert(comp != ushort.max,
                         "Can't register system \"" ~ SystemName
                             ~ "\" due to non existing component.");
@@ -876,7 +878,7 @@ export struct EntityManager
             foreach (iii, comp_info; components_info.readonly)
             {
                 ushort comp = components_map.get(cast(char[]) comp_info.type, ushort.max);
-                version (D_BetterC)
+                version (NoDRuntime)
                     assert(comp != ushort.max,
                         "Can't register system \"" ~ SystemName
                             ~ "\" due to non existing component.");
@@ -888,7 +890,7 @@ export struct EntityManager
             foreach (iii, comp_info; components_info.mutable)
             {
                 ushort comp = components_map.get(cast(char[]) comp_info.type, ushort.max);
-                version (D_BetterC)
+                version (NoDRuntime)
                     assert(comp != ushort.max,
                         "Can't register system \"" ~ SystemName
                             ~ "\" due to non existing component.");
@@ -1198,7 +1200,7 @@ export struct EntityManager
         {
             ushort comp = external_dependencies_map.get(cast(const(char)[]) comp_info.type,
                 ushort.max);
-            version (D_BetterC)
+            version (NoDRuntime)
                 assert(comp != ushort.max,
                     "Can't register system \"" ~ SystemName
                         ~ "\" due to non existing dependency.");
@@ -1211,7 +1213,7 @@ export struct EntityManager
         foreach (iii, comp_info; components_info.writableDeps)
         {
             ushort comp = external_dependencies_map.get(cast(char[]) comp_info.type, ushort.max);
-            version (D_BetterC)
+            version (NoDRuntime)
                 assert(comp != ushort.max,
                     "Can't register system \"" ~ SystemName
                         ~ "\" due to non existing dependency.");
@@ -1305,7 +1307,7 @@ export struct EntityManager
         //     static assert(0, "Add \"mixin ECS.Component;\" in top of component structure;");
         // }
 
-        static if (__traits(hasMember, Comp.init, "onDestroy") && isFunction!(Comp.onDestroy)
+        static if (hasMember!(Comp, "onDestroy") && isFunction!(Comp.onDestroy)
             && is(ReturnType!(Comp.onDestroy) == void)
             && Parameters!(Comp.onDestroy).length == 0)
         {
@@ -1317,7 +1319,7 @@ export struct EntityManager
             info.destroy_callback = &callDestroy;
         }
 
-        static if (__traits(hasMember, Comp.init, "onCreate") && isFunction!(Comp.onCreate)
+        static if (hasMember!(Comp, "onCreate") && isFunction!(Comp.onCreate)
             && is(ReturnType!(Comp.onCreate) == void) && Parameters!(Comp.onCreate).length == 0)
         {
             static void callCreate(void* pointer) nothrow @nogc
@@ -1856,6 +1858,7 @@ export struct EntityManager
     */
     export EntityTemplate* allocateTemplate(EntityTemplate* copy_tmpl)
     {
+        assert(copy_tmpl, "copy_tmpl can't be null");
         EntityTemplate* tmpl = Mallocator.make!EntityTemplate;
         tmpl.info = copy_tmpl.info;
         tmpl.entity_data = Mallocator.makeArray(copy_tmpl.entity_data);
@@ -1870,46 +1873,66 @@ export struct EntityManager
     */
     export EntityInfo* getEntityInfo(ushort[] ids)
     {
+        if(ids.length == 0)ids = null;
         EntityInfo* info = entities_infos.get(ids, null);
         if (info is null)
         {
             info = Mallocator.make!EntityInfo;
 
-            info.components = Mallocator.makeArray(ids);
-            info.deltas = Mallocator.makeArray!ushort(ids[$ - 1] + 1);
-
             info.size = EntityID.sizeof;
             info.alignment = EntityID.alignof;
 
-            info.tmpl_deltas = Mallocator.makeArray!ushort(ids[$ - 1] + 1, ushort.max);
-            uint components_size = EntityID.sizeof;
-
-            foreach (i, id; ids)
+            if(ids is null)
             {
-                info.alignment = max(info.alignment, components[id].alignment);
-                alignNum(info.size, components[id].alignment);
-                info.tmpl_deltas[id] = info.size;
-                info.size += components[id].size;
-                components_size += components[id].size;
+                uint block_memory = cast(uint)(
+                    m_page_size - EntitiesBlock.sizeof - info.size);
+                uint entites_in_block = block_memory / info.size;
+                info.max_entities = cast(ushort) entites_in_block;
             }
-            alignNum(info.size, info.alignment);
-
-            uint block_memory = cast(uint)(
-                m_page_size - EntitiesBlock.sizeof - (info.size - components_size));
-            //uint entity_comps_size = EntityID.sizeof;
-            uint mem_begin = EntitiesBlock.sizeof;
-
-            uint entites_in_block = block_memory / info.size; //entity_comps_size;
-            info.max_entities = cast(ushort) entites_in_block;
-            ushort current_delta = cast(ushort)(mem_begin + entites_in_block * EntityID.sizeof);
-
-            foreach (i, id; ids)
+            else 
             {
-                if (current_delta == 0)
-                    current_delta = ushort.max;
-                alignNum(current_delta, components[id].alignment);
-                info.deltas[id] = cast(ushort) current_delta;
-                current_delta += entites_in_block * components[id].size;
+                uint components_size = EntityID.sizeof;
+
+                info.components = Mallocator.makeArray(ids);
+                info.deltas = Mallocator.makeArray!ushort(ids[$ - 1] + 1);
+                info.tmpl_deltas = Mallocator.makeArray!ushort(ids[$ - 1] + 1, ushort.max);
+
+                foreach (i, id; ids)
+                {
+                    info.alignment = max(info.alignment, components[id].alignment);
+                    alignNum(info.size, components[id].alignment);
+                    info.tmpl_deltas[id] = info.size;
+                    info.size += components[id].size;
+                    components_size += components[id].size;
+                }
+                alignNum(info.size, info.alignment);
+
+                uint block_memory = cast(uint)(
+                    m_page_size - EntitiesBlock.sizeof - (info.size - components_size));
+                //uint entity_comps_size = EntityID.sizeof;
+                uint mem_begin = EntitiesBlock.sizeof;
+
+                uint entites_in_block = block_memory / info.size; //entity_comps_size;
+                info.max_entities = cast(ushort) entites_in_block;
+                ushort current_delta = cast(ushort)(mem_begin + entites_in_block * EntityID.sizeof);
+
+                foreach (i, id; ids)
+                {
+                    if (current_delta == 0)
+                        current_delta = ushort.max;
+                    alignNum(current_delta, components[id].alignment);
+                    info.deltas[id] = cast(ushort) current_delta;
+                    current_delta += entites_in_block * components[id].size;
+                }
+
+                info.comp_add_info = Mallocator.makeArray!(EntityInfo*)(info.deltas.length);
+                info.comp_rem_info = Mallocator.makeArray!(EntityInfo*)(info.deltas.length);
+
+                foreach (comp; info.components)
+                {
+                    info.comp_add_info[comp] = info;
+                    info.comp_rem_info[comp] = null;
+                }
             }
 
             info.systems = Mallocator.makeArray!bool(systems.length);
@@ -1930,15 +1953,6 @@ export struct EntityManager
                 addSystemCaller(*info, cast(uint) i);
             }
 
-            info.comp_add_info = Mallocator.makeArray!(EntityInfo*)(info.deltas.length);
-            info.comp_rem_info = Mallocator.makeArray!(EntityInfo*)(info.deltas.length);
-
-            foreach (comp; info.components)
-            {
-                info.comp_add_info[comp] = info;
-                info.comp_rem_info[comp] = null;
-            }
-
             entities_infos.add(info.components, info);
 
             generateListeners(info);
@@ -2502,7 +2516,7 @@ export struct EntityManager
     *Params:
     *id = ID of entity to be copyied.
     */
-    export Entity* addEntityCopy(EntityID id) nothrow @nogc
+    export Entity* addEntityCopy(EntityID id)
     {
         Entity* entity = getEntity(id);
         EntitiesBlock* block = getMetaData(entity);
@@ -2552,9 +2566,9 @@ export struct EntityManager
     use you should save ID instead of pointer.
     
     Params:
-    tmpl = pointer entity template allocated by EntityManager.
+    tmpl = pointer entity template allocated by EntityManager. Can be null in which case empty entity would be added (entity without components)
     */
-    export Entity* addEntity(EntityTemplate* tmpl) nothrow @nogc
+    export Entity* addEntity(EntityTemplate* tmpl)
     {
         return addEntity(tmpl, null);
     }
@@ -2564,12 +2578,14 @@ export struct EntityManager
     use you should save ID instead of pointer.
     
     Params:
-    tmpl = pointer entity template allocated by EntityManager.
+    tmpl = pointer entity template allocated by EntityManager. Can be null in which case empty entity would be added (entity without components)
     replacement = list of components references to used. Memory form list replace data from template inside new entity. Should be used only for data which vary between most entities (like 3D position etc.)
     */
-    export Entity* addEntity(EntityTemplate* tmpl, ComponentRef[] replacement) nothrow @nogc
+    export Entity* addEntity(EntityTemplate* tmpl, ComponentRef[] replacement)
     {
-        EntityInfo* info = tmpl.info;
+        EntityInfo* info = void;
+        if(tmpl)info = tmpl.info;
+        else info = getEntityInfo(null);
 
         ushort index = 0;
         EntitiesBlock* block;
@@ -2664,7 +2680,7 @@ export struct EntityManager
     /************************************************************************************************************************
     Return block with free space for selected EntityInfo. Additional this function is multithread safe.
     */
-    private EntitiesBlock* findBlockWithFreeSpaceMT(EntityInfo* info) nothrow @nogc
+    private EntitiesBlock* findBlockWithFreeSpaceMT(EntityInfo* info)
     {
         EntitiesBlock* block = info.last_block;
 
@@ -2718,7 +2734,7 @@ export struct EntityManager
     Params:
     id = id of entity to remove
     */
-    export void removeEntity(EntityID id) nothrow @nogc
+    export void removeEntity(EntityID id)
     {
         threads[threadID].entitesToRemove.add(id);
     }
@@ -3341,6 +3357,16 @@ export struct EntityManager
         export ~this() nothrow @nogc
         {
         }
+
+        export void opAssign(ComponentInfo c)
+        {
+            size = c.size;
+            alignment = c.alignment;
+            init_data = c.init_data;
+            destroy_callback = c.destroy_callback;
+            create_callback = c.create_callback;
+        }
+
         ///Component size
         ushort size;
         ///Component data alignment
@@ -3446,7 +3472,7 @@ export struct EntityManager
                     break;
                 }
             }
-            if (id > components[$ - 1])
+            if (components.length == 0 || id > components[$ - 1])
                 ids[len++] = id;
 
             assert(len == components.length + 1);
diff --git a/source/bubel/ecs/std.d b/source/bubel/ecs/std.d
index 879fcd5..8a3e207 100644
--- a/source/bubel/ecs/std.d
+++ b/source/bubel/ecs/std.d
@@ -7,11 +7,9 @@ License: BSD 3-clause, see LICENSE file in project root folder.
 */
 module bubel.ecs.std;
 
-version (Emscripten) version = ECSEmscripten;
-
 import std.traits;
 
-version (ECSEmscripten)
+version (Emscripten)
 {
     extern (C) struct pthread_mutex_t
     {
@@ -29,10 +27,6 @@ version (ECSEmscripten)
 
     extern (C) int memcmp(const void* s1, const void* s2, size_t size);
     extern (C) void exit(int status) nothrow @nogc;
-    extern (C) void __assert(const(char)* msg, const(char)* file, uint line)
-    {
-        exit(-20);
-    }
 
     extern (C) void free(void*) @nogc nothrow @system;
     extern (C) void* malloc(size_t size) @nogc nothrow @system;
@@ -60,7 +54,7 @@ else
     public import core.stdc.stdlib : qsort;
 }
 
-version (ECSEmscripten)
+version (Emscripten)
 {
 }
 else version (Windows)
@@ -89,7 +83,7 @@ else version (Posix)
     import core.sys.posix.stdlib : posix_memalign;
 }
 
-version (ECSEmscripten)
+version (Emscripten)
 {
     private const uint max_alloca = 10000;
     private __gshared byte[max_alloca] alloca_array;
@@ -279,7 +273,7 @@ static struct Mallocator
 
         static if (__traits(isPOD, T))
         {
-            __gshared T init = T.init;
+            __gshared immutable T init = T.init;
             memcpy(ret, &init, T.sizeof);
         }
         else static if (is(T == struct))
@@ -294,7 +288,7 @@ static struct Mallocator
             posix_memalign(&ret, alignment, length); //ret = aligned_alloc(alignment, length);
         else version (Windows)
             ret = _aligned_malloc(length, alignment);
-        else version (ECSEmscripten)
+        else version (Emscripten)
             posix_memalign(&ret, alignment, length); //malloc(length);
         else
             static assert(0, "Unimplemented platform!");
@@ -341,7 +335,7 @@ static struct Mallocator
             free(cast(void*) object);
         else version (Windows)
             _aligned_free(cast(void*) object);
-        else version (ECSEmscripten)
+        else version (Emscripten)
             free(cast(void*) object);
         else
             static assert(0, "Unimplemented platform!");
@@ -351,7 +345,7 @@ static struct Mallocator
 struct Mutex
 {
 
-    version (ECSEmscripten)
+    version (Emscripten)
     {
         void initialize() nothrow @nogc
         {
diff --git a/source/bubel/ecs/system.d b/source/bubel/ecs/system.d
index 24098c0..310b53a 100644
--- a/source/bubel/ecs/system.d
+++ b/source/bubel/ecs/system.d
@@ -13,14 +13,14 @@ import bubel.ecs.manager;
 System contain data required to proper glue EntityManager with Systems.
 System callbacks:
 $(LIST
-    * void onUpdate(EntitesData);
+    * void onUpdate(EntitiesData);
     * void onEnable() - called inside system.enable() function
     * void onDisable() - called inside system.disable() function
     * bool onBegin() - called inside manager.begin()
     * void onEnd() - called inside manager.end()
     * void onCreate() - called after registration inside registerSystem function
     * void onDestroy() - called during re-registration and inside manager destructor
-    * void onAddEntity(EntitesData) - called for every entity which are assigned to system (by adding new entity or changing its components)
+    * void onAddEntity(EntitiesData) - called for every entity which are assigned to system (by adding new entity or changing its components)
     * void onRemoveEntity(EntitiesData) - called for every entity removed from system update process
     * void onChangeEntity(EntitiesData) - called for every entity which components are changed but it was previously assigned to system
     * void handleEvent(Entity*, Event) - called for every event supported by system
@@ -108,7 +108,7 @@ struct System
 package:
 
     ///destory system. Dispose all data
-    void destroy() nothrow @nogc
+    export void destroy() nothrow @nogc
     {
         import bubel.ecs.std : Mallocator;
 
diff --git a/tests/basic.d b/tests/basic.d
index 084500a..ea54382 100644
--- a/tests/basic.d
+++ b/tests/basic.d
@@ -113,6 +113,31 @@ struct EmptySystem
     int count = 0;
 }
 
+struct EntityCounterSystem
+{
+    mixin ECS.System!1;
+
+    struct EntitiesData
+    {
+        int thread_id;
+        uint length;
+        Entity[] entity;
+    }
+
+    bool onBegin()
+    {
+        count = 0;
+        return true;
+    }
+
+    void onUpdate(EntitiesData data)
+    {
+        count += data.length;
+    }
+
+    int count = 0;
+}
+
 void beforeEveryTest()
 {
     becsID!CUnregistered = ushort.max;
@@ -243,7 +268,82 @@ unittest
     gEntityManager.commit();
     entity3 = gEntityManager.getEntity(id);
     assert(!entity3.getComponent!CUnregistered);
+}
 
+@("AddEmptyEntity")
+unittest
+{
+    struct OnAddRemoveChangeCounter
+    {
+        mixin ECS.System!1;
+
+        struct EntitiesData
+        {
+            int thread_id;
+            uint length;
+            Entity[] entity;
+        }
+
+        void onAddEntity(EntitiesData data)
+        {
+            add += data.length;
+        }
+        
+        void onRemoveEntity(EntitiesData data)
+        {
+            assert(0, "It's impossible to remove entity from being updated by system which accept empty entity");
+        }
+
+        int add = 0;
+    }
+
+    gEntityManager.beginRegister();
+
+    gEntityManager.registerSystem!EntityCounterSystem(0);
+    gEntityManager.registerSystem!OnAddRemoveChangeCounter(1);
+
+    gEntityManager.endRegister();
+
+    CLong long_component = CLong(3);
+
+    Entity* entity = null;
+    EntityID entity_id = gEntityManager.addEntity(null).id;
+
+    EntityCounterSystem* system = gEntityManager.getSystem!EntityCounterSystem;
+    assert(system !is null);
+    assert(system.count == 0);
+
+    OnAddRemoveChangeCounter* add_remove_change_system = gEntityManager.getSystem!OnAddRemoveChangeCounter;
+    assert(add_remove_change_system !is null);
+    assert(add_remove_change_system.add == 0);
+
+    gEntityManager.commit();
+    assert(add_remove_change_system.add == 1);
+
+    entity = gEntityManager.getEntity(entity_id);
+    assert(!entity.hasComponent(becsID!CLong));
+    assert(entity.getComponent(becsID!CLong) is null);
+    
+
+    gEntityManager.begin();
+    gEntityManager.update();
+    assert(system.count == 1);
+    gEntityManager.end();
+
+    gEntityManager.addEntityCopy(entity_id);
+    gEntityManager.addEntityCopy(entity_id);
+    gEntityManager.addComponents(entity_id, [ComponentRef(&long_component, becsID(long_component))].staticArray);
+    gEntityManager.commit();
+    assert(add_remove_change_system.add == 3, "onAddEntity missed");
+
+    entity = gEntityManager.getEntity(entity_id);
+    assert(entity.hasComponent(becsID!CLong));
+    assert(*entity.getComponent!CLong == 3);
+
+    gEntityManager.begin();
+    gEntityManager.update();
+    assert(system.count == 3);
+    gEntityManager.end();
 }
 
 //allocate templates
diff --git a/tests/bugs.d b/tests/bugs.d
index 1a3968c..10a3c62 100644
--- a/tests/bugs.d
+++ b/tests/bugs.d
@@ -142,5 +142,34 @@ unittest
     gEntityManager.update();
     gEntityManager.end();
 
+    gEntityManager.destroy();
+}
+
+@("2-empty-entity-crash")
+unittest
+{
+    
+    gEntityManager.initialize(0);
+
+    gEntityManager.beginRegister();
+
+    gEntityManager.registerComponent!CInt;
+    gEntityManager.registerComponent!CFloat;
+
+    gEntityManager.endRegister();
+
+
+    EntityTemplate* tmpl = gEntityManager.allocateTemplate([becsID!CInt, becsID!CFloat].staticArray);
+    scope(exit) gEntityManager.freeTemplate(tmpl);
+
+    EntityID id = gEntityManager.addEntity(tmpl).id;
+    // EntityID id2 = gEntityManager.addEntity().id;
+
+    gEntityManager.commit();
+
+    gEntityManager.removeComponents(id, [becsID!CInt, becsID!CFloat].staticArray);
+
+    gEntityManager.commit();
+
     gEntityManager.destroy();
 }
\ No newline at end of file
diff --git a/tests/meson.build b/tests/meson.build
index c530e3e..ff1a3a1 100644
--- a/tests/meson.build
+++ b/tests/meson.build
@@ -13,9 +13,9 @@ tests_src = files(
 exe = executable('BubelECSTests',
 	tests_src,
 	include_directories : [inc, include_directories('..')],
-	# d_args : args,
-	# link_args : link_args,
-	dependencies : bubel_ecs_dep,
+	d_args : args,
+	link_args : link_args,
+	dependencies : decs_dep,
 )
 
 test('basic-tests', exe)
diff --git a/tests/tests.d b/tests/tests.d
index 5205818..164eb30 100644
--- a/tests/tests.d
+++ b/tests/tests.d
@@ -645,7 +645,7 @@ version (unittest)
 else:
 	extern (C) int main()
 {
-	version (D_BetterC)printf("BetterC\n");
+
 	void dispatch(EntityManager.JobGroup jobs) nothrow @nogc
 	{
 		foreach (job; jobs.jobs)
diff --git a/xmake.lua b/xmake.lua
deleted file mode 100644
index 873a69f..0000000
--- a/xmake.lua
+++ /dev/null
@@ -1,116 +0,0 @@
-add_rules("mode.debug", "mode.release")
-
-if get_config("toolchain") == "ldc" then
-    add_ldflags("-linker=lld", {force = true})
-end
-
-option("betterC")
-    set_default(false)
-    if get_config("toolchain") == "gdc" then
-        add_dcflags("-fno-druntime")
-    elseif get_config("toolchain") == "dmd" then
-        add_dcflags("-betterC") -- DMD doesn't need -betterC flag during linking!?
-        add_ldflags("-betterC", {force = true})
-        add_shflags("-betterC", {force = true})
-    else
-        add_ldflags("-betterC", {force = true}) -- -betterC flag isn't accepted for LDC for some reason
-        add_dcflags("-betterC", {force = true})
-        add_shflags("-betterC", {force = true})
-    end 
-
-target("bubel-ecs")
-    set_kind("shared")
-    set_basename("BubelECS")
-    add_files("source/bubel/**.d")
-    add_includedirs("source", {public = true})
-    set_options("betterC")
-
-target("tests")
-    set_kind("binary")
-    set_basename("BubelECSTests")
-    add_ldflags("-L-rpath=.", {force = true})
-    add_files("tests/*.d|tests.d")
-    add_includedirs(".", {public = true})
-    set_options("betterC")
-    add_deps("bubel-ecs")
-    add_dcflags("-unittest")
-
-target("test")
-    set_kind("binary")
-    set_basename("BubelECSTest")
-    -- add_rpathdirs(".") -- this doesn't work completely
-    add_ldflags("-L-rpath=.", {force = true})
-    add_files("tests/tests.d")
-    add_includedirs(".", {public = true})
-    set_options("betterC")
-    add_deps("bubel-ecs")
-
---
--- If you want to known more usage about xmake, please see https://xmake.io
---
--- ## FAQ
---
--- You can enter the project directory firstly before building project.
---
---   $ cd projectdir
---
--- 1. How to build project?
---
---   $ xmake
---
--- 2. How to configure project?
---
---   $ xmake f -p [macosx|linux|iphoneos ..] -a [x86_64|i386|arm64 ..] -m [debug|release]
---
--- 3. Where is the build output directory?
---
---   The default output directory is `./build` and you can configure the output directory.
---
---   $ xmake f -o outputdir
---   $ xmake
---
--- 4. How to run and debug target after building project?
---
---   $ xmake run [targetname]
---   $ xmake run -d [targetname]
---
--- 5. How to install target to the system directory or other output directory?
---
---   $ xmake install
---   $ xmake install -o installdir
---
--- 6. Add some frequently-used compilation flags in xmake.lua
---
--- @code
---    -- add debug and release modes
---    add_rules("mode.debug", "mode.release")
---
---    -- add macro defination
---    add_defines("NDEBUG", "_GNU_SOURCE=1")
---
---    -- set warning all as error
---    set_warnings("all", "error")
---
---    -- set language: c99, c++11
---    set_languages("c99", "c++11")
---
---    -- set optimization: none, faster, fastest, smallest
---    set_optimize("fastest")
---
---    -- add include search directories
---    add_includedirs("/usr/include", "/usr/local/include")
---
---    -- add link libraries and search directories
---    add_links("tbox")
---    add_linkdirs("/usr/local/lib", "/usr/lib")
---
---    -- add system link libraries
---    add_syslinks("z", "pthread")
---
---    -- add compilation and link flags
---    add_cxflags("-stdnolib", "-fno-strict-aliasing")
---    add_ldflags("-L/usr/local/lib", "-lpthread", {force = true})
---
--- @endcode
---
-