More of a lifestyle than a game.
Since it's a first-person shooter (FPS), the game lends itself to twitchy type - someone able to drive a keyboard and mouse at the same time, clicking and jumping and shooting and dodging handgrenades - but you can set difficultly level of the computer AI in single player so that even novice players can have a thrilling and rewarding experience.
The real joy of BF2, however, is the online-multiplayer experience. Not only do you get to play with up to 63 other players in hot intense battlefield action, but you get scored on your performance, a score that allows you to increase in rank and unlock upgraded weapons. This score makes BF2 kinda like an RPG: as you progress through ranks, you try to improve your overall stats and awards. These stats and awards are affected by your performance in battle (rather than the other way around) but they buy you bragging rights in the hundreds of BF2 communities around the web.
So, whether you're a hard-core FPS gamer who can track their history back to Wolfenstein 3D or whether you're a noob who still can't use a mouse to look around a virtual battlefield, BF2 is sure to give you a challenging and thrilling ride.