Game is easy as hell until lvl 19, after that, every stage takes like, 15 minutes to play, and at least i lost at least 3 times ea on every one of them. This game is pretty much useless, even though the concept is good.
We get about a million types of guns but never get the chance to use them
To beat the turtle just have your units keep running towards him, at some point, theyll get there, if not, upgrade their speed.... this works with all the bosses