diff --git a/src/Collections/EcsGroup.cs b/src/Collections/EcsGroup.cs
index f1a46bd..fe112d7 100644
--- a/src/Collections/EcsGroup.cs
+++ b/src/Collections/EcsGroup.cs
@@ -18,100 +18,107 @@ namespace DCFApixels.DragonECS
     {
         private readonly EcsGroup _source;
 
-        #region Constructors
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsReadonlyGroup(EcsGroup source) => _source = source;
-        #endregion
-
         #region Properties
-        public bool IsNull => _source == null;
+        public bool IsNull
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _source == null; }
+        }
         public int WorldID
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _source.WorldID;
+            get { return _source.WorldID; }
         }
         public EcsWorld World
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _source.World;
+            get { return _source.World; }
         }
         public int Count
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _source.Count;
+            get { return _source.Count; }
         }
         public int CapacityDense
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _source.CapacityDense;
+            get { return _source.CapacityDense; }
         }
-        public int CapacitySparce
+        public int CapacitySparce //TODO remove
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _source.CapacitySparce;
+            get { return _source.CapacitySparce; }
         }
         public bool IsReleazed
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _source.IsReleased;
+            get { return _source.IsReleased; }
         }
         public int this[int index]
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _source[index];
+            get { return _source[index]; }
+        }
+        #endregion
+
+        #region Constructors
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public EcsReadonlyGroup(EcsGroup source)
+        {
+            _source = source;
         }
         #endregion
 
         #region Methods
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool Has(int entityID) => _source.Has(entityID);
+        public bool Has(int entityID) { return _source.Has(entityID); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int IndexOf(int entityID) => _source.IndexOf(entityID);
+        public int IndexOf(int entityID) { return _source.IndexOf(entityID); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsGroup.Enumerator GetEnumerator() => _source.GetEnumerator();
+        public EcsGroup.Enumerator GetEnumerator() { return _source.GetEnumerator(); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsGroup Clone() => _source.Clone();
+        public EcsGroup Clone() { return _source.Clone(); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int[] Bake() => _source.Bake();
+        public int[] Bake() { return _source.Bake(); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int Bake(ref int[] entities) => _source.Bake(ref entities);
+        public int Bake(ref int[] entities) { return _source.Bake(ref entities); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void Bake(List<int> entities) => _source.Bake(entities);
+        public void Bake(List<int> entities) { _source.Bake(entities); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsSpan ToSpan() => _source.ToSpan();
+        public EcsSpan ToSpan() { return _source.ToSpan(); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsSpan ToSpan(int start, int length) => _source.ToSpan(start, length);
+        public EcsSpan ToSpan(int start, int length) { return _source.ToSpan(start, length); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsGroup.LongsIterator GetLongs() => _source.GetLongs();
+        public EcsGroup.LongsIterator GetLongs() { return _source.GetLongs(); }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int First() => _source.First();
+        public int First() { return _source.First(); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int Last() => _source.Last();
+        public int Last() { return _source.Last(); }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool SetEquals(EcsReadonlyGroup group) => _source.SetEquals(group._source);
+        public bool SetEquals(EcsGroup group) { return _source.SetEquals(group); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool SetEquals(EcsGroup group) => _source.SetEquals(group);
+        public bool SetEquals(EcsReadonlyGroup group) { return _source.SetEquals(group._source); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool SetEquals(EcsSpan span) => _source.SetEquals(span);
+        public bool SetEquals(EcsSpan span) { return _source.SetEquals(span); }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool Overlaps(EcsReadonlyGroup group) => _source.Overlaps(group._source);
+        public bool Overlaps(EcsGroup group) { return _source.Overlaps(group); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool Overlaps(EcsGroup group) => _source.Overlaps(group);
+        public bool Overlaps(EcsReadonlyGroup group) { return _source.Overlaps(group._source); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool Overlaps(EcsSpan span) => _source.Overlaps(span);
+        public bool Overlaps(EcsSpan span) { return _source.Overlaps(span); }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool IsSubsetOf(EcsReadonlyGroup group) => _source.IsSubsetOf(group._source);
+        public bool IsSubsetOf(EcsGroup group) { return _source.IsSubsetOf(group); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool IsSubsetOf(EcsGroup group) => _source.IsSubsetOf(group);
+        public bool IsSubsetOf(EcsReadonlyGroup group) { return _source.IsSubsetOf(group._source); }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool IsSupersetOf(EcsReadonlyGroup group) => _source.IsSupersetOf(group._source);
+        public bool IsSupersetOf(EcsGroup group) { return _source.IsSupersetOf(group); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public bool IsSupersetOf(EcsGroup group) => _source.IsSupersetOf(group);
+        public bool IsSupersetOf(EcsReadonlyGroup group) { return _source.IsSupersetOf(group._source); }
         #endregion
 
         #region Internal
@@ -127,23 +134,23 @@ namespace DCFApixels.DragonECS
 #pragma warning disable CS0809 // Устаревший член переопределяет неустаревший член
         [Obsolete("Equals() on EcsGroup will always throw an exception. Use the equality operator instead.")]
         [EditorBrowsable(EditorBrowsableState.Never)]
-        public override bool Equals(object obj) => throw new NotSupportedException();
+        public override bool Equals(object obj) { throw new NotSupportedException(); }
         [Obsolete("GetHashCode() on EcsGroup will always throw an exception.")]
         [EditorBrowsable(EditorBrowsableState.Never)]
-        public override int GetHashCode() => throw new NotSupportedException();
+        public override int GetHashCode() { throw new NotSupportedException(); }
 #pragma warning restore CS0809 // Устаревший член переопределяет неустаревший член
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static implicit operator EcsSpan(EcsReadonlyGroup a) => a.ToSpan();
+        public static implicit operator EcsSpan(EcsReadonlyGroup a) { return a.ToSpan(); }
         #endregion
     }
 
     [DebuggerTypeProxy(typeof(DebuggerProxy))]
-    public unsafe class EcsGroup : IDisposable, IEnumerable<int>, IEntityStorage
+    public class EcsGroup : IDisposable, IEnumerable<int>, IEntityStorage
     {
         private EcsWorld _source;
         private int[] _dense;
         private int[] _sparse;
-        private int _count;
+        private int _count = 0;
         internal bool _isReleased = true;
 
         #region Properties
@@ -167,7 +174,7 @@ namespace DCFApixels.DragonECS
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get => _dense.Length;
         }
-        public int CapacitySparce
+        public int CapacitySparce //TODO remove
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get => _sparse.Length;
@@ -188,7 +195,7 @@ namespace DCFApixels.DragonECS
             get
             {
 #if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-                if (index < 0 || index >= Count) Throw.ArgumentOutOfRange();
+                if (index < 0 || index >= Count) { Throw.ArgumentOutOfRange(); }
 #endif
                 return _dense[++index];
             }
@@ -205,12 +212,13 @@ namespace DCFApixels.DragonECS
         {
             _source = world;
             _source.RegisterGroup(this);
-            _dense = new int[denseCapacity];
+            _dense = new int[denseCapacity]; //TODO добавить в конфиг мира значение
             _sparse = new int[world.Capacity];
-
-            _count = 0;
         }
-        public void Dispose() => _source.ReleaseGroup(this);
+        public void Dispose()
+        {
+            _source.ReleaseGroup(this);
+        }
         #endregion
 
         #region Has/IndexOf
@@ -227,39 +235,51 @@ namespace DCFApixels.DragonECS
         #endregion
 
         #region Add/Remove
-        public void AddUnchecked(int entityID) => AddInternal(entityID);
+        public void AddUnchecked(int entityID)
+        {
+            Add_Internal(entityID);
+        }
         public bool Add(int entityID)
         {
             if (Has(entityID))
+            {
                 return false;
-            AddInternal(entityID);
+            }
+            Add_Internal(entityID);
             return true;
         }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        internal void AddInternal(int entityID)
+        internal void Add_Internal(int entityID)
         {
 #if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            if (Has(entityID)) Throw.Group_AlreadyContains(entityID);
+            if (Has(entityID)) { Throw.Group_AlreadyContains(entityID); }
 #endif
             if (++_count >= _dense.Length)
+            {
                 Array.Resize(ref _dense, _dense.Length << 1);
+            }
             _dense[_count] = entityID;
             _sparse[entityID] = _count;
         }
 
-        public void RemoveUnchecked(int entityID) => RemoveInternal(entityID);
+        public void RemoveUnchecked(int entityID)
+        {
+            Remove_Internal(entityID);
+        }
         public bool Remove(int entityID)
         {
-            if (!Has(entityID))
+            if (Has(entityID) == false)
+            {
                 return false;
-            RemoveInternal(entityID);
+            }
+            Remove_Internal(entityID);
             return true;
         }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        internal void RemoveInternal(int entityID)
+        internal void Remove_Internal(int entityID)
         {
 #if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            if (!Has(entityID)) Throw.Group_DoesNotContain(entityID);
+            if (!Has(entityID)) { Throw.Group_DoesNotContain(entityID); }
 #endif
             _dense[_sparse[entityID]] = _dense[_count];
             _sparse[_dense[_count--]] = _sparse[entityID];
@@ -271,7 +291,9 @@ namespace DCFApixels.DragonECS
             foreach (var e in this)
             {
                 if (!_source.IsUsed(e))
-                    RemoveInternal(e);
+                {
+                    Remove_Internal(e);
+                }
             }
         }
         #endregion
@@ -280,24 +302,44 @@ namespace DCFApixels.DragonECS
         public void Clear()
         {
             _count = 0;
-            //массив _dense нет смысла очищать
             for (int i = 0; i < _sparse.Length; i++)
+            {
                 _sparse[i] = 0;
+            }
         }
         #endregion
 
         #region CopyFrom/Clone/Bake/ToSpan
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public void CopyFrom(EcsReadonlyGroup group) => CopyFrom(group.GetSource_Internal());
         public void CopyFrom(EcsGroup group)
         {
 #if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            if (group.World != _source) throw new ArgumentException("groupFilter.WorldIndex != WorldIndex");
+            if (group.World != _source) { Throw.Group_ArgumentDifferentWorldsException(); }
 #endif
             if (_count > 0)
+            {
                 Clear();
+            }
             foreach (var item in group)
-                AddInternal(item);
+            {
+                Add_Internal(item);
+            }
+        }
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void CopyFrom(EcsReadonlyGroup group)
+        {
+            CopyFrom(group.GetSource_Internal());
+        }
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void CopyFrom(EcsSpan span)
+        {
+            if (_count > 0)
+            {
+                Clear();
+            }
+            for (int i = 0; i < span.Length; i++)
+            {
+                Add_Internal(span[i]);
+            }
         }
         public EcsGroup Clone()
         {
@@ -314,7 +356,9 @@ namespace DCFApixels.DragonECS
         public int Bake(ref int[] entities)
         {
             if (entities.Length < _count)
+            {
                 entities = new int[_count];
+            }
             Array.Copy(_dense, 1, entities, 0, _count);
             return _count;
         }
@@ -334,10 +378,7 @@ namespace DCFApixels.DragonECS
         {
             start -= 1;
 #if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
-            if (start < 0 || start + length > _count)
-            {
-                Throw.ArgumentOutOfRange();
-            }
+            if (start < 0 || start + length > _count) { Throw.ArgumentOutOfRange(); }
 #endif
             return new EcsSpan(WorldID, _dense, start, length);
         }
@@ -357,7 +398,7 @@ namespace DCFApixels.DragonECS
 #endif
             foreach (var item in group)
                 if (!Has(item))
-                    AddInternal(item);
+                    Add_Internal(item);
         }
         public void UnionWith(EcsSpan span)
         {
@@ -367,7 +408,7 @@ namespace DCFApixels.DragonECS
             foreach (var item in span)
             {
                 if (!Has(item))
-                    AddInternal(item);
+                    Add_Internal(item);
             }
         }
         #endregion
@@ -405,7 +446,7 @@ namespace DCFApixels.DragonECS
                 {
                     int item = _dense[i];
                     if (group.Has(item))
-                        RemoveInternal(item);
+                        Remove_Internal(item);
                 }
             }
             else
@@ -413,7 +454,7 @@ namespace DCFApixels.DragonECS
                 foreach (var item in group)
                 {
                     if (Has(item))
-                        RemoveInternal(item);
+                        Remove_Internal(item);
                 }
             }
         }
@@ -425,7 +466,7 @@ namespace DCFApixels.DragonECS
             foreach (var item in span)
             {
                 if (Has(item))
-                    RemoveInternal(item);
+                    Remove_Internal(item);
             }
         }
         #endregion
@@ -444,7 +485,7 @@ namespace DCFApixels.DragonECS
             {
                 int item = _dense[i];
                 if (!group.Has(item))
-                    RemoveInternal(item);
+                    Remove_Internal(item);
             }
         }
         #endregion
@@ -461,9 +502,9 @@ namespace DCFApixels.DragonECS
 #endif
             foreach (var item in group)
                 if (Has(item))
-                    RemoveInternal(item);
+                    Remove_Internal(item);
                 else
-                    AddInternal(item);
+                    Add_Internal(item);
         }
         #endregion
 
@@ -472,9 +513,9 @@ namespace DCFApixels.DragonECS
         {
             foreach (var item in _source.Entities)
                 if (Has(item))
-                    RemoveInternal(item);
+                    Remove_Internal(item);
                 else
-                    AddInternal(item);
+                    Add_Internal(item);
         }
         #endregion
 
@@ -587,7 +628,7 @@ namespace DCFApixels.DragonECS
 #endif
             EcsGroup result = a._source.GetFreeGroup();
             foreach (var item in a)
-                result.AddInternal(item);
+                result.Add_Internal(item);
             foreach (var item in b)
                 result.Add(item);
             return result;
@@ -602,7 +643,7 @@ namespace DCFApixels.DragonECS
             EcsGroup result = a._source.GetFreeGroup();
             foreach (var item in a)
                 if (!b.Has(item))
-                    result.AddInternal(item);
+                    result.Add_Internal(item);
             return result;
         }
         /// <summary>as Intersect sets</summary>
@@ -615,7 +656,7 @@ namespace DCFApixels.DragonECS
             EcsGroup result = a._source.GetFreeGroup();
             foreach (var item in a)
                 if (b.Has(item))
-                    result.AddInternal(item);
+                    result.Add_Internal(item);
             return result;
         }
 
@@ -629,10 +670,10 @@ namespace DCFApixels.DragonECS
             EcsGroup result = a._source.GetFreeGroup();
             foreach (var item in a)
                 if (!b.Has(item))
-                    result.AddInternal(item);
+                    result.Add_Internal(item);
             foreach (var item in b)
                 if (!a.Has(item))
-                    result.AddInternal(item);
+                    result.Add_Internal(item);
             return result;
         }
 
@@ -641,7 +682,7 @@ namespace DCFApixels.DragonECS
             EcsGroup result = a._source.GetFreeGroup();
             foreach (var item in a._source.Entities)
                 if (!a.Has(item))
-                    result.AddInternal(item);
+                    result.Add_Internal(item);
             return result;
         }
         #endregion
@@ -723,32 +764,22 @@ namespace DCFApixels.DragonECS
         public override string ToString()
         {
             return CollectionUtility.EntitiesToString(_dense.Skip(1).Take(_count), "group");
-            //return $"group({_count}) {{{string.Join(", ", _dense.Skip(1).Take(_count).OrderBy(o => o))}}}";
         }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int First()
-        {
-            return _dense[1];
-        }
+        public int First() { return _dense[1]; }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int Last()
-        {
-            return _dense[_count];
-        }
+        public int Last() { return _dense[_count]; }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        internal void OnWorldResize(int newSize)
-        {
-            Array.Resize(ref _sparse, newSize);
-        }
+        internal void OnWorldResize(int newSize) { Array.Resize(ref _sparse, newSize); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static implicit operator EcsReadonlyGroup(EcsGroup a) => a.Readonly;
+        public static implicit operator EcsReadonlyGroup(EcsGroup a) { return a.Readonly; }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static implicit operator EcsSpan(EcsGroup a) => a.ToSpan();
+        public static implicit operator EcsSpan(EcsGroup a) { return a.ToSpan(); }
         internal class DebuggerProxy
         {
             private EcsGroup _group;
-            public EcsWorld World => _group.World;
-            public bool IsReleased => _group.IsReleased;
+            public EcsWorld World { get { return _group.World; } }
+            public bool IsReleased { get { return _group.IsReleased; } }
             public EntitySlotInfo[] Entities
             {
                 get
@@ -762,11 +793,11 @@ namespace DCFApixels.DragonECS
                     return result;
                 }
             }
-            public int Count => _group.Count;
-            public int CapacityDense => _group.CapacityDense;
-            public int CapacitySparce => _group.CapacitySparce;
-            public override string ToString() => _group.ToString();
-            public DebuggerProxy(EcsGroup group) => _group = group;
+            public int Count { get { return _group.Count; } }
+            public int CapacityDense { get { return _group.CapacityDense; } }
+            public int CapacitySparce { get { return _group.CapacitySparce; } }
+            public override string ToString() { return _group.ToString(); }
+            public DebuggerProxy(EcsGroup group) { _group = group; }
             public DebuggerProxy(EcsReadonlyGroup group) : this(group.GetSource_Internal()) { }
         }
         #endregion
diff --git a/src/Collections/EcsSpan.cs b/src/Collections/EcsSpan.cs
index 8f0a26d..1a03d80 100644
--- a/src/Collections/EcsSpan.cs
+++ b/src/Collections/EcsSpan.cs
@@ -14,29 +14,29 @@ namespace DCFApixels.DragonECS
         private readonly ReadOnlySpan<int> _values;
 
         #region Properties
+        public bool IsNull
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get { return _worldID == 0; }
+        }
         public int WorldID
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _worldID;
+            get { return _worldID; }
         }
         public EcsWorld World
         {
-            get => EcsWorld.GetWorld(_worldID);
+            get { return EcsWorld.GetWorld(_worldID); }
         }
-        public int Length
+        public int Length //TODO rename to Count
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _values.Length;
+            get { return _values.Length; }
         }
         public int this[int index]
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _values[index];
-        }
-        public bool IsNull
-        {
-            [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _worldID == 0;
+            get { return _values[index]; }
         }
         #endregion
 
@@ -51,7 +51,7 @@ namespace DCFApixels.DragonECS
         internal EcsSpan(int worldID, int[] array)
         {
             _worldID = worldID;
-            _values = array;
+            _values = new ReadOnlySpan<int>(array);
         }
         internal EcsSpan(int worldID, int[] array, int length)
         {
@@ -70,15 +70,15 @@ namespace DCFApixels.DragonECS
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public int[] Bake()
         {
-            int[] result = new int[_values.Length];
-            _values.CopyTo(result);
-            return result;
+            return _values.ToArray();
         }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public int Bake(ref int[] entities)
         {
             if (entities.Length < _values.Length)
+            {
                 Array.Resize(ref entities, _values.Length);
+            }
             int[] result = new int[_values.Length];
             _values.CopyTo(result);
             return _values.Length;
@@ -95,42 +95,40 @@ namespace DCFApixels.DragonECS
         #endregion
 
         #region operators
-        public static bool operator ==(EcsSpan left, EcsSpan right) => left._values == right._values;
-        public static bool operator !=(EcsSpan left, EcsSpan right) => left._values != right._values;
+        public static bool operator ==(EcsSpan left, EcsSpan right) { return left._values == right._values; }
+        public static bool operator !=(EcsSpan left, EcsSpan right) { return left._values != right._values; }
         #endregion
 
         #region Enumerator
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public ReadOnlySpan<int>.Enumerator GetEnumerator() => _values.GetEnumerator();
+        public ReadOnlySpan<int>.Enumerator GetEnumerator() { return _values.GetEnumerator(); }
         #endregion
 
         #region Other
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsSpan Slice(int start) => new EcsSpan(_worldID, _values.Slice(start));
+        public EcsSpan Slice(int start) { return new EcsSpan(_worldID, _values.Slice(start)); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public EcsSpan Slice(int start, int length) => new EcsSpan(_worldID, _values.Slice(start, length));
+        public EcsSpan Slice(int start, int length) { return new EcsSpan(_worldID, _values.Slice(start, length)); }
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public int[] ToArray() => _values.ToArray();
-
-#pragma warning disable CS0809 // Устаревший член переопределяет неустаревший член
-        [Obsolete("Equals() on EcsSpan will always throw an exception. Use the equality operator instead.")]
-        [EditorBrowsable(EditorBrowsableState.Never)]
-        public override bool Equals(object obj) => throw new NotSupportedException();
-        [Obsolete("GetHashCode() on EcsSpan will always throw an exception.")]
-        [EditorBrowsable(EditorBrowsableState.Never)]
-        public override int GetHashCode() => throw new NotSupportedException();
-#pragma warning restore CS0809 // Устаревший член переопределяет неустаревший член
+        public int[] ToArray() { return _values.ToArray(); }
         public override string ToString()
         {
             return CollectionUtility.EntitiesToString(_values.ToArray(), "span");
-            //return $"span({_values.Length}) {{{string.Join(", ", _values.ToArray().OrderBy(o => o))}}}";
         }
+#pragma warning disable CS0809 // Устаревший член переопределяет неустаревший член
+        [Obsolete("Equals() on EcsSpan will always throw an exception. Use the equality operator instead.")]
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override bool Equals(object obj) { throw new NotSupportedException(); }
+        [Obsolete("GetHashCode() on EcsSpan will always throw an exception.")]
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public override int GetHashCode() { throw new NotSupportedException(); }
+#pragma warning restore CS0809 // Устаревший член переопределяет неустаревший член
 
         internal class DebuggerProxy
         {
             private int[] _values;
             private int _worldID;
-            public EcsWorld World => EcsWorld.GetWorld(_worldID);
+            public EcsWorld World { get { return EcsWorld.GetWorld(_worldID); } }
             public EntitySlotInfo[] Entities
             {
                 get
@@ -144,7 +142,7 @@ namespace DCFApixels.DragonECS
                     return result;
                 }
             }
-            public int Count => _values.Length;
+            public int Count { get { return _values.Length; } }
             public DebuggerProxy(EcsSpan span)
             {
                 _values = new int[span.Length];
diff --git a/src/EcsAspect.cs b/src/EcsAspect.cs
index ce6c633..4d1162d 100644
--- a/src/EcsAspect.cs
+++ b/src/EcsAspect.cs
@@ -200,7 +200,7 @@ namespace DCFApixels.DragonECS
                 group.Clear();
                 var enumerator = GetEnumerator();
                 while (enumerator.MoveNext())
-                    group.AddInternal(enumerator.Current);
+                    group.Add_Internal(enumerator.Current);
             }
             public int CopyTo(ref int[] array)
             {