Foof, that's a lot of thoughts in a comment block!

Character.cs

@@ -547,11 +547,45 @@ public void Update()
 
 			if (Opponent != null)
 			{
-				//TODO Check for pushbox overlap
-				//I don't think I can hack that. Getting them to mirror right was bad enough.
+				//Kafe.Me.Window.Title = "...";
+				for (var mine = 0; mine < boxes.Count; mine++)
+				{
+					var myBox = boxes[mine];
+					var myType = boxTypes[mine];
+					var doneHere = false;
+					for (var theirs = 0; theirs < Opponent.boxes.Count && !doneHere; theirs++)
+					{
+						var theirBox = Opponent.boxes[theirs];
+						var theirType = Opponent.boxTypes[theirs];
+						if (!myBox.Intersects(theirBox, Position, Opponent.Position))
+							continue;
+						//Kafe.Me.Window.Title = string.Format("Boxes touch! #s {0} and {1}, types {2} and {3}", mine, theirs, myType, theirType);
+						if (myType == BoxTypes.Push && theirType == BoxTypes.Push)
+						{
+							//TODO: Okay. OKAY! Now we just need to determine how deeply we penetrate.
+							/* In Capcom fighters, if you walk into a stationary opponent your speed is halved and your opponent is moved away with the other half.
+							 * If you walk into an opponent who himself walks towards you, it cancels out.
+							 * Therefore, assuming let's say a velocity of 2.0...
+							 * Walk into stationary: velocity is halved to 1.0, opponent's velocity gains -1.0 (- because away from you)
+							 * Walk into walking: velocity is halved to 1.0, opponent starts at 2.0 but gains -1.0, so 2.0 + -1.0 = 1.0
+							 * ...but then *they* walk into *you* as well, so they affect you in turn...
+							 * ...so their 1.0 is halved into 0.5, and your 1.0 gains -0.5 and you end up both having 0.5 velocity.
+							 * If positions are int-clipped this should end up effectively not moving at all then.
+							 */
+							doneHere = true;
+							break;
+						}
+						else if (myType == BoxTypes.Vulnerable && theirType == BoxTypes.Attack)
+						{
+							//TODO: We're the one's being hit, so it's on us to react.
+							doneHere = true;
+							break;
+						}
+					}
+				}
 			}
 
-			Position = new Vector2(Position.X + (FacingLeft ? -Velocity.X : Velocity.X), Position.Y);
+			Position = new Vector2(Position.X + (FacingLeft ? -Velocity.X : Velocity.X), Position.Y).ToInteger();
 
 			if (inputTimer > 0)
 			{

Extensions.cs

@@ -19,6 +19,15 @@ public static string ToShort(this Rectangle rect)
 		{
 			return string.Format("<{0},{1},{2},{3}>", rect.X, rect.Y, rect.Width, rect.Height);
 		}
+
+		public static bool Intersects(this Rectangle a, Rectangle b, Vector2 originA, Vector2 originB)
+		{
+			var aX = a.X + originA.X;
+			var aY = a.Y + originA.Y;
+			var bX = b.X + originB.X;
+			var bY = b.Y + originB.Y;
+			return (bX < aX + a.Width && aX < bX + b.Width && bY < aY + a.Height && aY < bY + b.Height);
+		}
 	}
 
     public static class InputExtensions

Game.cs

@@ -112,7 +112,7 @@ protected override void LoadContent()
 				for (var i = 0; i < numNames; i++)
 				{
 					names[i] = Args[i + 1].ToLowerInvariant();
-					colors[i] = 0;
+					colors[i] = 1;
 					if (names[i].Contains(","))
 					{
 						colors[i] = int.Parse(names[i].Substring(names[i].IndexOf(',') + 1));