This game is wonderful, it kept me sane while deployed in Iraq.

The game has some campaign modes, as well as multiplayer. This is a non-linear game with a mildy steep learning curve. You have diplomatic and strategic things to consider as well as research and developement. The Doomsday expansion added spies.

You can play a major player during world war 2, or a minor power. You can pick you're cabinent, set you're nations political outlook.

Its really a multi-layered game, and you will spend hours playing it. The replayability is very high, as you will want to try out different nations, and different approaches to the game, like naval based, or ground based, or air based.

In some of the campaigns there are some minor linear features, like when wars brake out, or major historical things occured.