Call of Duty 2, one of a kind, if you dont include the gazillion other WWII games.
You play the game as three seperate armies as you fight the German army.
You'll start out fighting for the Russian army, and as you progress you will eventually unlock the British campaign. In the British Campaign, where you will fight the Jerries, as they are called in the Egyptian desert, where you will have the opertunity to use the tanks, note that this is the only campaign that has tanks on your side, the other 2 have no tanks, not even ones that are controlled by the computer, just the enemy. After finishing the British campaign, you will unlock the the american campaign. Which is kinda like the campaigns one and two. Once you unlock the american campaign, you will eventually tire of the game because they seem to be the same, just you and your comrades will have different uniforms in each one.
Once you get tired of the single player mode, you will be able to kill your friends in the multiplayer, either split screen or you can go online and kill people around the world. The only problem with this game is the game will lag, and when that happens you will be completely unable to play due to a lack of any sort of control. However when you do get to play, you'll definately have fun with the variety of games, you'll of course have the familiars, like deathmatch and capture the flag, but you'll also have a few new games that aren't usually found in most games.
The graphics are all very nice, most the NPC's in your group or the enimies all have a unique face that will seem very familiar to you when you all fight together, however that wont stop you from not knowing who is on your team and who isn't, which will allow you to kill your team and force you to start again. On the harder difficulties, you will need to know who is who because you be forced to shoot faster and more accurate because they will be killing you faster than than you can say "Damn you German bastards."
The sound has a high quality. Each weapon, every soldier, and every vehicle has a sound that is similar only to another one of those thing, except each soldier, they all sound good and unique, as they should, because they dont need to all say the same German insults over and over again.
After going through this game, you will find alot of fun playing this game, with constant hours of playing each level over and over again. However, to warn you, this replay value will only come from the AI that the enemy has, no matter what the difficulty, the computer will challenge you reflexes. This game should be worth the time playing, however, the multiplayer aspect should be skipped and only played on Perfect Dark Zero, with its wide variety and 32 player games, Call of Duty simply just doesnt stand up to half of what Perfect Dark offers, however, the single player is worth playing and does alot of things better than Perfect Dark Zero.