Simple and we've seen it all before.
The game is way to simple. I appreciate that you don't have to start every single mission from the start when you are attacked, but you're respawned a few feet away, with full energy. The zombies are left with the same health as when you died, which offers hardly any challenge. On several occasions, my mission was to reach a certain destination that was blocked by a single hoard of zombies, I'd get attacked, and then I would respawn in the location I was trying to get to. That's a little too convenient.
There was a continuity issues that bothered the hell out of me in this game. When you receive missions, sometimes the quest giver will use the words "you guys" or "all of you" and things to that effect and during cutscenes, the characters you didn't select when you began the game are present in the cutscenes. No explanation is ever given as to why these characters are allegedly with me during the mission and are not actually there to assist me. They just happen to appear during cutscenes and apparently the NPCs in the game thing they're with you as well.
The graphics are not bad at all, in fact there's alot of detail here but there seems to be a few collision detection issues. The game is short and unoriginal. The story is run of the mill, the gameplay is run of the mill, and the graphics are the only outstanding thing here, but even that has it's issues.