I'm curious. How is Zombie Apocalypse, compared to the PSN game, Dead Nation?
Like I mentioned above, I find ZA1 to be abysmal. ZA2 is like Dead Nation in that you walk around dark streets and blast zombies. I've only played about the first 3 levels of each game, but it feels like Dead Nation has quite a bit more when it comes to upgrading and seems to be the more polished game. Dead Nation only allows for 2 player co-op I believe, where ZA2 allows up to 4 players. Dead Nation also seemed significantly more difficult as well. The tone of the two games are quite different as well (Dead Nation is pretty dark, where as ZA2 is pretty corny).
I preferred my time with Dead Nation quite a bit more, even though I did die more.