add simple crash logic

theGame/Game.cs

@@ -60,13 +60,28 @@ namespace theGame
 
 		}
 
-		public void DoMoves()
-		{
-			for (int i = 0; i < rocks.Count; i++)
-			{
-				rocks[i].positionX--;
-			}
-			     
-		}
+        public void DoMoves()
+        {
+            for (int i = 0; i < rocks.Count; i++)
+            {
+                rocks[i].positionX--;
+            }
+
+            int deleted_rock_index = -1;
+
+            for (int i = 0; i < rocks.Count; i++)
+            {
+                if (rocks[i].positionX ==  playerCraft.positionX && rocks[i].positionY == playerCraft.positionY)
+                {
+                    deleted_rock_index = i;
+                    playerCraft.Health = playerCraft.Health - 15;
+                }
+            }
+
+            if (deleted_rock_index >= 0)
+            {
+                rocks.RemoveAt(deleted_rock_index);
+            }
+        }
 	}
 }