Good idea, but...
First, in story mode, I think ennemies shouldn't just spawn all over. Second, these ennemies shouldn't be able to shoot you when they're off the screen. I know, it's probably a bitch to code this, but it looks like it was sort of rushed in terms of bugs in the game. The jumping is alright, but the only thing that bugged me is that it's not really evident where you have to go in the story mode. You have to jump up on stuff that doesn't look like it can be jumped on. Also, the enemies take too many damn shots to kill.. it's retarded to the point where i shot a guy 5 times in the head before he went down.
The game would have been better balanced if the enemies had less HP, because they always seem to respawn. Or if they had the same if not more HP, but did not respawn. I understand zombies not dying right away, but regular enemies should be killed in 2 or 3 hits, not 5 or 7.
Overall though, good game. The story mode was a nice addition.