A game that should be appreciated most by fans of COD4 and Left 4 Dead.
The campaign of COD5 has you playing as two different characters, an American named Pvt. Miller and a Russian named Pvt. Petrenko. Each campaign is short, but if you put the two together you get a campaign of decent-length. It's very cinematic and pretty fun. At times there are battles of epic scale that inspire awe with the player. But the campaign alone doesn't generate enough value for a purchase.
The multiplayer component of COD5 is very good. It has many great maps and many great modes. Its even fun, and deep, outside of actually playing. You can organize your weapons, classes, attachments, perks, and clan tag.(mine is 'ZAP!') You're bound to have a lot of fun playing multiplayer.
My personal favorite part of the game is Nazi Zombies. You, alone or with others, have to defned yourself in a large house from an infinite wave of nazi zombies. It is unlocked after you beat the single-player campaign. You can do two-player splitscreen or two-to-four players on Live.
You can also play through levels in the campaign co-operatively or competitively. Competitive play is fun because you and the other player are trying to top the other in enemy kills. Getting kills with short periods of time in between each other can raise your score multiplier, and REALLY raise your score.
So, if you liked COD4 and Left 4 Dead, Call of Duty: World at War is a game you're very likely to enjoy.