This was a decent game, but the NPCs were ridiculously stupid, making most of the later attempts to escort them through giant hordes of zombies nearly impossible (these are not necessary to complete the game, of course). One or two NPCs are manageable, but more than that and they'll get stuck and eaten.
I hate timed missions, and that's all this game is but I was still able to enjoy it despite that and the fact that the gameplay is a little rough around the edges. Definitely worth a look, especially for $30.