As others have said, needs more polish. Also less dubstep, but that's a subjective opinion.
The zombies didn't act like zombies; zombies don't jump and use their hands to help them over obstacles. Their make-up was rather all over the place, too.
Don't use shaky cam, get a tripod or something.
The slow-mo is a bit clichéd, maybe try it elsewhere, or just don't use it at all.