It's a good game kill time but when you start to play competitive it's another story. In PVP mode there is alot of unfairness going on. When I'm stuck at wave 3-4 my rivals are way ahead of me due to lack of power ups I get. This happens especially on survival mode. The amount of time I lost due to not being able to kill the 1st boss in time is unbelievable. I think everyone should get the same power ups at every single wave so it's becomes a game of skill rather than luck.