"Explosive, enjoyable action and Zombies "
While the WW2 era is starting to get fairly overused and boring in the gaming industry, Call of Duty 5 is a stellar title to fill the gap.
Singleplayer wise, you will fighting as a US marine and Russian soldier in the Pacific theatre of war and the Eastern front, usually underused in the WW2 genre of shooter games, which is a good thing as the Japanese and germans offer a larger variety of enemies - snipers in trees and banzai charges just to name a few. The Storyline is engaging enough however not to the extent of Brother in Arms or Call of Duty 4's to have believable tangible characters. While the Singleplayer is fun, many of the levels have poor level design, for instance, running through a trench being killed at the same point by the same mounted machine gun is not fun, it is frustrating. The lack of flanking however does not give you any choice. Respawning enemies with invisible triggers can frustrate you more.
Multiplayer wise, World at war excels above Call of duty 4. World at war has kept all the best parts of cod4's multiplayer (killstreaks and perks) and replaced much of the aspects of it's predecessor with more enjoyable alternatives. Weapons feel more balanced and has all the substance of previous titles in the franchise that made the games fun.
Co-op is a nice feature to this game, the singleplayer campaign is playable co-operatively online with strangers or friends and the Nazi zombies mode, which puts you and 3 others against an endless horde of zombies is excellent fun
Graphics is a hit and miss, In parts it looks spectacular with brilliant lighting, explosive set pieces and some superb character models however there are times where the low res textures and animations will come in, but Generally the game looks and runs great with these graphics