The campaign, though a bit short, is amazing, and the multiplayer provides hours of fun.
So, Gears of War 2 is a pretty amazing little game. Whether or not you liked the first game in the series, I'd highly suggest picking this one up. I loved Gears of War, and it was one of the first games I played on an Xbox 360 way back. The story was very well written, I loved how badass everyone were, even though I find it a bit stupid att imes, a bit cliche if you want.
The story pretty much picks up where the last one ended, some time along. Once again you will have to fight the disgusting monsters lurking below, and you'll have to go underground and take on beasts a hundred times your size. The combat system is highly similar to that of the original, with some minor improvements with regards to reaction. Of course, the game is linear, though there are some parts where you can pick from two different paths. It doesn't matter which one you pick as you'll end up in the same spot, and I can almost guarantee you'll play this game twice, so you'll be able to get all the content.
The multiplayer is really fun. Though it's tough to play online for a noobie like me, I think it's absolutely awesome to play with a couple of my buddies. I still get crushed and destroyed, but like most other shooter games, be it 3rd person or 1st person, it just is a lot more fun when y ou can smack talk your buddies. There's a variety of different game modes and the lobbies are highly customizable, so you can really do whatever you want when you play with a couple of buddies.
My only complaint is that the matchmaking system online will place you against people on an entirely different skill level more often than not, and you'll often get crushed or simply destroy the opposing team. The campaign, though amazing and great fun, cuold definitely be longer.