First 5-20 lvls was good.. but at 45.. its like the game have ended.. nothing gives exp as it did in the start.. its like its not made to come this far.
3/5 since Easy is made to hard.
and later when you know what tower to build, it get to easy and you just need to w8 until the map is done. since the Easy is to hard you cant build whatever you feel for, you have to build same at every map so you dont die, and thats crap.