I liked this tower defense game for the first few hours. The art and overall style is charming and the mechanics are somewhat unique (focused on optimal timing of weapon reloading), although the variety and strategy are somewhat limited. After about level 14, however, I started feeling like the game was tuned more to get money from me and not for fun. When the levels get harder, you cant realistically replay earlier levels for points to upgrade your weapons--youll get about 100 points for replaying a level but it costs thousands to level up your weapons. Super-powered weapons are introduced early in the game but the special, consumable, energy required to use them is doled out so frugally that you could easily use it up just learning how to use the weapons and have none when you really need it. There is no way to earn more of that energy without real money. Of course, it would be fair to say the game is just too challenging for me, but nonetheless, it feels like a game that lost its purpose somewhere on the hunt for in-app purchases. Ive played and loved (and given 5 star ratings to) brutally difficult games that were fun even though I could never make it past the first few levels. Ive spent hours perfecting runs and completing games that I probably should have given up on because they were just out of my league--but they were just so awesome. This is not one of those games.