I've been saying that for years, but nobody would listen
Well, considering that the game is a few years old now, I expect that most people have a system that would actually run the game (although you might want to run an FPS config). It's a game with a very casual atmosphere (the cartoon graphics might help with that
) and a lot of humor (which you might or might not get when you're new to the game). Even if you can't aim, the game is easy on you with classes like medic or engineer. If your aim is a bit less shitty you can probably play with the projectile based classes (SHOOT ROCKET AT FEET).
Underneath the cartoon graphics is a very good shooter though. This might not be obvious at first glance, especially if you don't know anything about shooters. But the config of the game, the part that decides when you can respawn and where, how score is calculated, is very good compared to a lot of shooters. Almost every shooter revolves about hitscan weapons ("bullets"), and all these games have issues with hit registration. But the game lacks every form of realism (besides gravity), and that's what people like in games like Call of Duty (which I think is a dull, slow and boring game).
And because that's too much text, here's one of the game's official promotion trailers: