Lots of complaints about ads. I agree they are annoying. That said, I am reinstalling this game after a year or two away, because I remember it being a very fun mindless way to kill some time. I never purchased anything and got pretty far; while it sounds like there are legit complaints about PvP matching and some bugs, the users saying it's impossible to win without paying are wrong. This style of game is just very hard at high levels :)