I find it quite amazing how much Free Radical pulled themselves together from the previous Timesplitters to this one. Oh my, they fixed just about EVERYTHING that was wrong with the first one and added a little more as well. The story mode actually has a story now. And above that, you actually have interaction with the story instead of just going from piont A to point B back to point A. The music sounds great now, to a degree, and the playable characters and usable weapons have been expanded upon greatly.
The game modes have also expanded, adding more 'crazy' challenges like in the first one, along with Arcade challenges much like the challenge mode in Perfect Dark.
I only rented it this past weekend, and I would love to buy it and advance through, but the fact is that the genre is dying. 3D shooters are much more prominent on the PC. Being good at console FPSs is like being good at Tetris these days. Nobody really cares. And you won't find anyone to play against you seriously or who takes the game seriously.
Oh well. If you do plan on investing in Timesplitters 2, I suggest you wait a couple months for the online version. That way you can branch out to those who also take the game seriously. All is not lost. Hmmm... I wonder if you'll be able to play against people on opposite consoles. That would make the game much more playable.. much more...