Kingdom Hearts~: Chain of Memories! xD Nope, not joking, I'm playing the next games too, hoping that they improved with each new release. And so far this game doesn't look as long as the first one, so maybe it'll be over fast :D Like I said to a friend the other day, casual gamers play what they like, true hardcore gamers play everything, whether they like it or not!
A far more enjoyable experience, and far shorter, was Modern Warfare 2. It gets better as you progress, and for me it only got really interesting by the end of the 2nd act. The 3rd and final act is just awesome from start to finish. Overall though, although it's better than the first, the impact is just not the same after 2 years with the same basic gameplay and graphics engine. It's a pretty good game, but unless you're serious about the online component, at the current price it's just a rip-off.