A decent single player campaign with addictive multiplayer make this a game worth buying...
I don't get why people hate this game just because its made by Treyarch. I reckon they did a good job on this. Yeah, when you play through the tough single player campaign you definitely get that 'Made by Treyarch' feeling but the sheer immersion and atmosphere of storming a pacific island, defending against banzai attacks and assaulting the Reichstag in the final hours of Berlin will keep you entertained.
Now, about the campaign, i love the pacific theater and the final Soviet advance into Berlin. But the campaign, as tough as it is on the harder levels is just too short. I finished it in about 10 hours worth of gameplay.
Where World at War really shines is the Multiplayer. In my opinion this makes up about 80% of the game. Just like COD4 it is the most fun, funniest and enjoyable online shooter out there. Everytime i play i LOL at something. The Nazi Zombie bonus level is also a blast to play through online.
The graphics are better than COD4, using an updated COD4 engine. The voice and sound is excellent, although the gun sounds could have used a bit more...umph! They sound weak compared to other shooters. Other than that its all good. The multiplayer is the best part of the game though...
Definitely worth buying...the single player will keep you immersed for about 10 hours but the multiplayer will probably keep you occupied for about 10 months...until the next Call of Duty :)