diff --git a/src/Collections/EcsGroup.cs b/src/Collections/EcsGroup.cs
index 997b4ce..150cc47 100644
--- a/src/Collections/EcsGroup.cs
+++ b/src/Collections/EcsGroup.cs
@@ -196,10 +196,12 @@ namespace DCFApixels.DragonECS
         {
             if (_groupSparsePagePoolCount <= 0)
             {
-                var x = UnmanagedArrayUtility.NewAndInit<int>(EcsGroup.PAGE_SIZE);
-                return x;
+                var newPage = UnmanagedArrayUtility.NewAndInit<int>(EcsGroup.PAGE_SIZE);
+                return newPage;
             }
-            return _groupSparsePagePool[--_groupSparsePagePoolCount];
+            var takedPage = _groupSparsePagePool[--_groupSparsePagePoolCount];
+            _groupSparsePagePool[_groupSparsePagePoolCount] = null;
+            return takedPage;
         }
         internal void ReturnPage(int* page)
         {
@@ -214,6 +216,16 @@ namespace DCFApixels.DragonECS
             }
             _groupSparsePagePool[_groupSparsePagePoolCount++] = page;
         }
+        private void DisposeGroupPages()
+        {
+            foreach (var page in _groupSparsePagePool)
+            {
+                if (page != null)
+                {
+                    UnmanagedArrayUtility.Free(page);
+                }
+            }
+        }
         #endregion
 
         #region Groups Pool
diff --git a/src/DebugUtils/MetaAttributes/EcsMetaAttribute.cs b/src/DebugUtils/MetaAttributes/EcsMetaAttribute.cs
index b95af50..74118f5 100644
--- a/src/DebugUtils/MetaAttributes/EcsMetaAttribute.cs
+++ b/src/DebugUtils/MetaAttributes/EcsMetaAttribute.cs
@@ -7,13 +7,12 @@ namespace DCFApixels.DragonECS.Core
 {
     public abstract class EcsMetaAttribute : Attribute { }
 
-
-    internal unsafe static class EcsMetaAttributeHalper
+    internal static class EcsMetaAttributeHalper
     {
         internal const string EMPTY_NO_SENSE_MESSAGE = "With empty parameters, this attribute makes no sense.";
         [ThreadStatic]
         private static string[] _splitBuffer;
-        public static string[] Split(char separator, string value)
+        public static unsafe string[] Split(char separator, string value)
         {
             if (_splitBuffer == null)
             {
@@ -46,7 +45,7 @@ namespace DCFApixels.DragonECS.Core
         }
 
         #region SplitStream
-        private ref struct SplitStream
+        private unsafe ref struct SplitStream
         {
             public string current;
             public char* ptr;
diff --git a/src/EcsAspect.cs b/src/EcsAspect.cs
index c1dc6e1..bd4f5d5 100644
--- a/src/EcsAspect.cs
+++ b/src/EcsAspect.cs
@@ -198,7 +198,7 @@ namespace DCFApixels.DragonECS
             #region Constructors/New
             private Builder() { }
 
-            internal static unsafe (TAspect aspect, EcsMask mask) New<TAspect>(EcsWorld world) where TAspect : new()
+            internal static (TAspect aspect, EcsMask mask) New<TAspect>(EcsWorld world) where TAspect : new()
             {
                 //Get Builder
                 if (_constructorBuildersStack == null)
diff --git a/src/EcsMask.cs b/src/EcsMask.cs
index bc58ee4..4579813 100644
--- a/src/EcsMask.cs
+++ b/src/EcsMask.cs
@@ -758,7 +758,7 @@ namespace DCFApixels.DragonECS
             [Il2CppSetOption(Option.NullChecks, false)]
             [Il2CppSetOption(Option.ArrayBoundsChecks, false)]
 #endif
-            public unsafe ref struct Enumerator
+            public ref struct Enumerator
             {
                 private ReadOnlySpan<int>.Enumerator _span;
 
@@ -784,7 +784,7 @@ namespace DCFApixels.DragonECS
                     get { return _span.Current; }
                 }
                 [MethodImpl(MethodImplOptions.AggressiveInlining)]
-                public bool MoveNext()
+                public unsafe bool MoveNext()
                 {
                     while (_span.MoveNext())
                     {
diff --git a/src/EcsWorld.cs b/src/EcsWorld.cs
index 1810d02..025f6a3 100644
--- a/src/EcsWorld.cs
+++ b/src/EcsWorld.cs
@@ -236,6 +236,7 @@ namespace DCFApixels.DragonECS
                 _isDestroyed = true;
                 _poolTypeCode_2_CmpTypeIDs = null;
                 _cmpTypeCode_2_CmpTypeIDs = null;
+                DisposeGroupPages();
 
                 foreach (var item in _executorCoures)
                 {
@@ -1054,6 +1055,11 @@ namespace DCFApixels.DragonECS
                     list.Add(_pools[poolIdsPtr[i]]);
                 }
             }
+
+            if (count >= BUFFER_THRESHOLD)
+            {
+                UnmanagedArrayUtility.Free(poolIdsPtr);
+            }
         }
         public ReadOnlySpan<object> GetComponentsFor(int entityID)
         {
diff --git a/src/Utils/DependencyGraph.cs b/src/Utils/DependencyGraph.cs
index c1bddb2..063a044 100644
--- a/src/Utils/DependencyGraph.cs
+++ b/src/Utils/DependencyGraph.cs
@@ -4,6 +4,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
+using System.Runtime.CompilerServices;
 
 namespace DCFApixels.DragonECS.Core
 {
@@ -70,7 +71,7 @@ namespace DCFApixels.DragonECS.Core
 
 
 
-    public unsafe class DependencyGraph<T> : IDependencyGraph<T>
+    public class DependencyGraph<T> : IDependencyGraph<T>
     {
         private readonly Dictionary<T, VertexID> _vertexIDs = new Dictionary<T, VertexID>(32);
         private StructList<VertexInfo> _vertexInfos = new StructList<VertexInfo>(32);
@@ -226,7 +227,7 @@ namespace DCFApixels.DragonECS.Core
         #endregion
 
         #region Sort
-        public T[] Sort()
+        public unsafe T[] Sort()
         {
             const int BUFFER_THRESHOLD = 256;
             if (_count <= BUFFER_THRESHOLD)
@@ -248,7 +249,7 @@ namespace DCFApixels.DragonECS.Core
                 return ConvertIdsToTsArray(buffer);
             }
         }
-        private void TopoSorting(UnsafeArray<VertexID> sortingBuffer)
+        private unsafe void TopoSorting(UnsafeArray<VertexID> sortingBuffer)
         {
             VertexID[] nodes = new VertexID[_count];
             var adjacency = new List<(VertexID To, int DependencyIndex)>[GetVertexInfosCount()];
@@ -336,7 +337,7 @@ namespace DCFApixels.DragonECS.Core
                 throw new InvalidOperationException("Cyclic dependency detected." + details);
             }
         }
-        private void ReoderInsertionIndexes(UnsafeArray<VertexID> sortingBuffer)
+        private unsafe void ReoderInsertionIndexes(UnsafeArray<VertexID> sortingBuffer)
         {
             for (int i = 0; i < GetVertexInfosCount(); i++)
             {
@@ -375,7 +376,7 @@ namespace DCFApixels.DragonECS.Core
 
             }
         }
-        private static void MoveElement<TValue>(ref UnsafeArray<TValue> array, int oldIndex, int newIndex) where TValue : unmanaged
+        private static unsafe void MoveElement<TValue>(ref UnsafeArray<TValue> array, int oldIndex, int newIndex) where TValue : unmanaged
         {
             if (oldIndex == newIndex) return;
 
@@ -405,7 +406,7 @@ namespace DCFApixels.DragonECS.Core
 
             ptr[newIndex] = item;
         }
-        private T[] ConvertIdsToTsArray(UnsafeArray<VertexID> buffer)
+        private unsafe T[] ConvertIdsToTsArray(UnsafeArray<VertexID> buffer)
         {
             T[] result = new T[buffer.Length];
             for (int i = 0; i < result.Length; i++)