Frustrating => Addicting => Rewarding

This was a really fun game once you start to get the knack of it.
There should be some kind of option to subit your high score on the last level.
Still trying to beat 11 min 52 seconds on the last level but thats a REDICULOUS wave of little green dudes.
I really like the system where the more health your castle has the more money you get.
The only real chage I'd make is making the prices of towers/buildings a bit cheaper.
The game is either won or lost before I can actually pull off the set ups I plan.