One of the most realistic FPS' i've played.
Online is fun. You have to level up by winning matches in Free For All, Team Deathmatch, War, Capture the Flag, and more! When you first start out, you go into Bootcamp, which you can stay in until level 8 if you want. Bootcamp is basically the noob area. Haha. There are also power ups you can get if you have enough kills. 3 is recon plane: See the enemies on your map
5 artillery: Drop bombs on the enemy
7 dogs: Send out dogs to hunt your enemy and kill them
If you get dogs, people are going to be mad at you, but who cares!? You're going to be win in no time! It's a 2 bite kill for the dogs. The problem is, the dogs can be killed off. Tanks are another cool feature online. You cant get in a tank and blow your enemy away. You can also get in the turret and blast the enemy to bits! I also like leveling up to unlock features and guns. The more you level up, the stronger guns and feature you unlock. Features are like Juggernaut, Bomb Squad, Steady Hip, and more!
Nazi zombies is a feature most people love in the game. Nazi zombies is a game where you're trapped in a house and zombies are trying to break in from bordered windows and you must kill them before they break in, fix the windows, and survive as many waves of zombies as possible. If you're past level 3, your knife is basically useless. The wave number you're on, the number of stabs it will take to kill the zombie. You can open doors, clear debree and open doors for more power ups and weapons, but more zombies! the random weapon box is a excellent feature. You can get a very strong, or very weak, gun. The strongest would be the laser gun, only available in Nazi zombies, and is an instant kill. Speaking of instant kill, let's speak of power ups. There are 3 Insta-kill, which is of course one hit kill, nuke, which kills all zombie instantly, and 2x points.
The co-op feature is fun, but can get annoying. You can play nazi zombies and story on co-op. The reason it can get annoying is because of healing. If you're playing with someone new, they're sure to die a lot, which mean you're on the opposite side of the map killing, you have to run all the way across the map, kill the enemies around them, and heal your partner in which you have to worry about not dieing and them dieing in the same time! It gets pretty annoying.
Another thing is checkpoints. There could be one person left and they can kill you and then you will die and have to kill the people in that area you just killed again!