diff --git a/Blocks/Behaviour/WalkthroughBehaviour.cs b/Blocks/Behaviour/WalkthroughBehaviour.cs
index bc83d9eaf..744c94b7e 100644
--- a/Blocks/Behaviour/WalkthroughBehaviour.cs
+++ b/Blocks/Behaviour/WalkthroughBehaviour.cs
@@ -85,7 +85,8 @@ namespace MCGalaxy.BlockBehaviour {
             p.checkpointX = x; p.checkpointY = y; p.checkpointZ = z;
             int index = p.level.PosToInt(x, y, z);
             if (index != p.lastCheckpointIndex) {
-                p.SpawnEntity(p, 0xFF, p.pos[0], (ushort)((y - 1) * 32 + 51), p.pos[2], p.rot[0], p.rot[1]);
+            	int sendY = (p.pos[1] / 32) * 32 + 10;
+            	p.SpawnEntity(p, 0xFF, p.pos[0], (ushort)sendY, p.pos[2], p.rot[0], p.rot[1]);
                 p.lastCheckpointIndex = index;
             }
             return true;
diff --git a/Levels/Physics/ExtraInfoPhysics.cs b/Levels/Physics/ExtraInfoPhysics.cs
index 6f378ae40..cf76ba1d0 100644
--- a/Levels/Physics/ExtraInfoPhysics.cs
+++ b/Levels/Physics/ExtraInfoPhysics.cs
@@ -41,8 +41,7 @@ namespace MCGalaxy.BlockPhysics {
                         door = true; break;
                 }
             }
-            if (!wait)
-                return false;
+            if (!wait) return false;
             
             if (door && C.time < 2) {
                 // TODO: perhaps do proper bounds checking
diff --git a/Levels/PhysicsArgs.cs b/Levels/PhysicsArgs.cs
new file mode 100644
index 000000000..a35bd7aa2
--- /dev/null
+++ b/Levels/PhysicsArgs.cs
@@ -0,0 +1,101 @@
+/*
+    Copyright 2015 MCGalaxy
+        
+    Dual-licensed under the Educational Community License, Version 2.0 and
+    the GNU General Public License, Version 3 (the "Licenses"); you may
+    not use this file except in compliance with the Licenses. You may
+    obtain a copy of the Licenses at
+    
+    http://www.opensource.org/licenses/ecl2.php
+    http://www.gnu.org/licenses/gpl-3.0.html
+    
+    Unless required by applicable law or agreed to in writing,
+    software distributed under the Licenses are distributed on an "AS IS"
+    BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+    or implied. See the Licenses for the specific language governing
+    permissions and limitations under the Licenses.
+ */
+using System;
+using System.Runtime.InteropServices;
+
+namespace MCGalaxy.BlockPhysics {
+
+    [StructLayout(LayoutKind.Sequential, Pack = 4)]
+    public struct PhysicsArgs {
+        public uint Raw;
+        
+        // Flags        
+        /// <summary> Whether this physics item should wait before performing its other arguments. </summary>
+        public bool Wait {
+            get { return (Raw & (1u << 0)) != 0; }
+            set { Raw &= ~(1u << 0);
+                Raw |= (value ? 1u : 0u) << 0; }
+        }
+        
+        /// <summary> Whether this physics item should randomly drop downards. </summary>
+        public bool Drop {
+            get { return (Raw & (1u << 1)) != 0; }
+            set { Raw &= ~(1u << 1);
+                Raw |= (value ? 1u : 0u) << 1; }
+        }
+        
+        /// <summary> Whether this physics item should randomly convert back into air. </summary>
+        public bool Dissipate {
+            get { return (Raw & (1u << 2)) != 0; }
+            set { Raw &= ~(1u << 2);
+                Raw |= (value ? 1u : 0u) << 2; }
+        }
+        
+        /// <summary> Whether this physics item should revert back into the given block id. </summary>
+        public bool Revert {
+            get { return (Raw & (1u << 3)) != 0; }
+            set { Raw &= ~(1u << 3);
+                Raw |= (value ? 1u : 0u) << 3; }
+        }        
+        
+        /// <summary> Whether this physics item should check itself and its neighbours for tdoor activation. </summary>
+        public bool Door {
+            get { return (Raw & (1u << 4)) != 0; }
+            set { Raw &= ~(1u << 4);
+                Raw |= (value ? 1u : 0u) << 4; }
+        }
+        
+        /// <summary> Whether this physics item should randomly explode. </summary>
+        public bool Explode {
+            get { return (Raw & (1u << 5)) != 0; }
+            set { Raw &= ~(1u << 5);
+                Raw |= (value ? 1u : 0u) << 5; }
+        }
+        
+        /// <summary> Whether this physics update should have a rainbow affect applied. </summary>
+        public bool Rainbow {
+            get { return (Raw & (1u << 6)) != 0; }
+            set { Raw &= ~(1u << 6);
+                Raw |= (value ? 1u : 0u) << 6; }
+        }
+        
+        // Data
+        public bool RandomRainbow {
+            get { return (Raw & (1u << 7)) != 0; }
+            set { Raw |= (value ? 1u : 0u) << 7; }
+        }
+        
+        public byte Value1 {
+            get { return (byte)(Raw >> 8); }
+            set { Raw &= ~(0xFFu << 8);
+                Raw |= (uint)value << 8; }
+        }
+        
+        public byte Value2 {
+            get { return (byte)(Raw >> 16); }
+            set { Raw &= ~(0xFFu << 16);
+                Raw |= (uint)value << 16; }
+        }
+        
+        public byte Value3 {
+            get { return (byte)(Raw >> 24); }
+            set { Raw &= ~(0xFFu << 24);
+                Raw |= (uint)value << 24; }
+        }
+    }
+}
diff --git a/MCGalaxy_.csproj b/MCGalaxy_.csproj
index 1f8578e12..3dd855792 100644
--- a/MCGalaxy_.csproj
+++ b/MCGalaxy_.csproj
@@ -470,6 +470,7 @@
     <Compile Include="Levels\Level.Blocks.cs" />
     <Compile Include="Levels\Level.Physics.cs" />
     <Compile Include="Levels\LevelInfo.cs" />
+    <Compile Include="Levels\PhysicsArgs.cs" />
     <Compile Include="Levels\Physics\AIPhysics.cs" />
     <Compile Include="Levels\Physics\AirPhysics.cs" />
     <Compile Include="Levels\Physics\BirdPhysics.cs" />