TRON 2.0 wasn't just quite decent, it was awesome, and it was very well received by critics at the time of release. Unfortunately, it sold about bugger all.
In any case it's certainly one of the best single player FPSs I have played, with great AI, gorgeous graphics, varied, unique weapons, good voice acting and a lightcycle game on the side. It's certainly better than about any single player FPS released since.