Though not being full-featured, or even sort of featured, PAM is only $9.99, so it's hard to come down on it with a vengeance. In fact, it's quite a bit of fun.
Trying to mix things up is a commendable effort, but P.A.M. just comes off as a lazy attempt to revive a previously saturated genre. If there were more tracks and game modes, there could've been a much better game to speak of here. As it stands, Post Apocalyptic Mayhem is a ridiculously overpriced download that you should not waste your money with.