The click area should be made bigger. I didn't realize I could kill the thing with the knife until I tried for the 5th time. Also, I wasn't able to unlock the door on my first try.
The zombie that makes the screen shake and makes skeletons is a bit overpowered. It has too big of a range. Instead, the attack should be lessened and it can produce more ground skeletons.
We'll add this to the list of things to look into, thanks!