THE GOOD: The graphics have been enhanced substantially, especially the character models. Mona Sax has got the hottest polygonal body ever. Max himself has shedded the constipation face he had in the orginal thankfully. MP2 expands upon the original's gameplay a bit by introducing an escort mission as well as a mission where you give cover fire for your allied npc. Otherwise it's largely the same hectic action that made MP such a hit.
THE BAD: MP2 feels more like an expansion pack than an outright sequel. Other than some minor differences the game feels and looks very much like the original.
BOTTOM LINE: While I don't think MP2 is worth full price I wouldn't hesitate to recommend it at $20 and lower. The changes to the game from the original MP are mainly cosmetic in nature but MP2 is a solid action shooter nonetheless.