Great fun on Xbox Live, Multiplayer, Campaign, and Special Ops
Campaign is one of the hardest things about the game. Easy is pretty easy, normal would be considered hard on other games, hard would be considered like Legendary on Halo, and Veteran is one of the hardest campaigns I have ever played. It gets frustrating at times, but is still fun. Surprises are around every corner of this game. I'm not going to spoil anything, but there are a lot of surprises. This game may seem short if you're playing on easy or normal, but in reality, there are 23 missions to complete. If that isn't satisfying enough, I don't know what to tell you.
Special Ops is a bunch of minigames you can play with a friend. Easy for 1 star, Normal for 2 stars, and Veteran for 3 stars. Special Ops is based of some of the sections of Campaign (for some missions) and extends it a bit, or adds enemies. Sometimes, it's completely different, but is similar.
This game is officially my favorite game, trust me, this game is the best of all the Call of Duty games, maybe even every shooter game!