Okay, if you're looking for some backstory after playing the free Enemy Territory expansion, look elsewhere.
Gameplay wise, Wolfenstein plays like Tomb Raider 1 for PS1; which you would expect had it not been released almost 5-7 years later! Many people think pacing should be sped up in games like Brothers in Arms and Elder Scrolls Oblivion. Wolfenstein should actually be slowed DOWN. Seriously, how can your character run 3x faster than a regular soldier in real life with a rocket launcher and THompson on him??? One of the worst problems was level design. All the levers, switches, dials, buttons, and enemy placement were wayyyyy to much to handle. Basically, you have to find the right combination of switches on the FIRST LEVEL IN THE GAME!!! Talk about giving the player a helping hand.
The guns are pretty cool, except all of them are waaayyyy to under-powered. The pistol takes about 15 shots to kill a zombie, which would be alright, except for the fact that the auto-aim makes you fire at its chest, instead of the head. Strangely, when you kick with the black button, you see a leg come out from the bottom of the screen, making it look like your leg's gona fall of any second.
Basically, you should not get this game. Maybe as a rental, since the multiplayer is quite good, but even then you can download an upgraded multiplayer expansion online for the PC, called ENEMY TERRITORY. Believe me, if your looking for a great single player game, look towards Gears of War or Splinter Cell: Double Agent, both of which also have great multiplayer componenets.