I'd agree with the other reviews regarding longevity etc - but this game is still very good. Graphics are superb and the movie clips portraying the story work well. There is a lack of variety in terms of the enemy (you're constantly killing stormtroopers or droids) and also with the levels, as you return to where you started in the final level.
The game play is very much improved on the first game and there are some devastating combos. A much better defence system when you can deflects shots and incoming lightsabers. You can also literally dismember the enemy as well.
It certainly flows better than the first and you don't have to go back 10mins to a check point if you die - something that was quite annoying in the first game, particularly on the harder difficulty.
I completed this on medium difficulty in about 6 hours or so - I'd recommend starting on Hard - at least that way you'd have more of a challenge.
If this game had a few more (non-repetive)levels, I think most people would have been satisfied. Even though I've completed it, as its a Star Wars game and is expertly written and designed - I think this will be a game I can pick up and play, but maybe not as much as I did with the first one.