My biggest pet peeve was the spelling and grammar issues, since I'm a writer and it really irked me. However, I can't really say anything about that, since it doesn't have much to do with the game.
The game itself was a nice pass time, something you could have a little bit of fun with. However, the controls are both slow and a little broken at times (I won't mention the glitches that others have mentioned). Also, the jumping system kind of rubs me the wrong way as well. I also feel like a bit of a story could have helped this go a long way.
I do enjoy the upgrade system and the skins, as well as the objectives you have to complete when finishing a level. I think this game is much better than some of the 1 star people are giving you credit for, although it needs improvements in a more varied soundtrack, faster controls, and a more interesting plot than a hack-n-slash game.