Well
The weapons were very nice, and fun to use. BUT, some of them clearly had no unique qualities to them, as others were just alike. And, several weapons were like this:one weapon was far better in stats than another, but only a little bit more expensive. All guns should be unique, and have prices that fit. Also, once I got into the stronger machine guns, I stopped aiming, and just sprayed. That's when it got boring. The massive blood was cool, but that combined with the shaking of the screen made it difficult to even see the zombies.
a "warzone cleanup" option would be nice. And better designed weapons. And better designed power ups. They were way too good, the experience ones.
But still, out of all the things I didn't like/would like to see improved, I still spent over a half hour playing. Fun game :)