Sorry I was unable to create the effect you wish
But I felt bad saying that without a result
So I had some things to your game
1) It now costs 150 to spawn in a block
2) You can rotate the block by Pressing R well placing it
3) There is no cash variable
4) When killing a zombie it will say +1 in orange to represent adding to the score.
Sorry that I wasn't able to fix your main problem!
New Version: dropbox.com/s/eg8axvuqvt4z51e/zombie.capx
If you want any other minor changes, just let me know! (I have to get offline now but send me a message)