Nazi Zombie Army 2 is a good game. Just want to get that out before I start.
The story to this game is pretty basic, something about piecing together this thing which will get rid of the zombies or something. It's really passable, but it's not meant to have a story in the first place.
Now, there are a few problems with it. The largest issue is the length. You can beat this game in probably 4 hours. However, you could argue that for the price it's allowed to be 4 hours. Now that's all opinion on how you like to spend your money, but for me, I would say for its 5 levels, it should be $10 rather than $15.
This game has some great atmosphere, the destroyed buildings, to the gloomy skies, and the orange deathly glows, overall, it makes it just a great experience. Although, I would say the level design is a hit and miss. It's good because it's varied; it's not the same thing repeated. It's a miss because the levels are kind of, well, not very exciting. I mean, there are some great parts, but it's more of, meh level design. Although, these levels do setup some very fun moments for sniping. This is all just my opinion though, and like I said, it still does have fun levels with varied designs, but the levels aren't mindblowing.
The real star here is the gameplay. It's still very fun to blow zombies heads off and kick them down on the ground and blow their head off. The gameplay just really makes the game and makes for a lot of replay value which pretty much overshadows the short game length. It should also be noted that this game is a little easier than the first, I reccomend Marksman or Sniper Elite. It's overall not as hard as the first, which is a little dissapointing, but there is always Sniper Elite difficulty. Also, this game is not NEARLY as enjoyable if not playing co-op. Co-op is how the game is ment to be played. You don't neccessarily need to be playing with people you know though, playing with random people is almost as fun. Although, this game doesn't do anything really different from the original. It's pretty much an add-on, for what is an add-on.
Overall, I love this game, and all the pros really overshadow the cons. It's a fantastic game, that doesn't really do anything different than the original, but it's still great. I reccomend picking the game up, especially if you have friends to play with!
EDIT: I forgot to mention the bullet cam. Well, it's still awesome :)