The simple review:
Single player is script-based and VERY boring. A lot of hunt the keys and open the doors. Gah.
Multiplayer can be fun, especially in the team modes or if you do a lot of Force pull/pushing to kill people by tossing them off ledges - you still get credited with a kill that way - I thought that was hilarious! There's no authentication scheme to multiplayer, so pirated copies and retail copies alike are all online playing. That's going to be one huge playerbase.
Gameplay itself is worse than the original JK, as in it's hard as hell to HIT a moving person in the game with the base guns. Saber battles are, like in the original Jedi Knight, as hit and miss as it gets. Not much skill involved in this - basically just start swinging and hope to get lucky. The three saber fight styles - basically short, medium and long strokes - make little to no difference in the end.
Graphics, excellent and fairly reminscent of the Quake III Arena engine. Level design? The common factor is a tendency to the annoyingly large and convoluted. Sound, superb but music is a little too Imperial. I'd prefer something more fast-paced. Techno saber fights!
It's good to see Kyle back in action but otherwise...$45+ on this? Not bloody likely.
Edit: Game played at 1024x768, no AA, on the system in my sig. Framerates were totally acceptable.