Awesome!
I just pretty much finished it, now going for the few remaining medals...
It's much better than the first. The one thing that bothered me here was the zombies whose torsos sometimes rise again after I kill them - this happens even if they're killed by a massive explosion or when I have double-damage active, and even if I notice them I have to wait until they actually get up in order to kill them... Oh, and maybe the machete/nightstick could have killed normal zombies in one hit, it's awfully weak now.
Other than that - great variety of enemies and weapons, challenging but not invincible bosses and mini-bosses, a really fun game! I don't like it very much that weapons are received randomly, but that's the style of these games, and this I think is the best so far I've played :)