Continuity mistake: In Nancy's final showdown dream, she goes down to the cellar, then goes to open the door which leads to the boiler room. When she opens the door it's hinged on her right hand side, yet when the shot changes the door is now hinged on her left hand side. (01:13:25)
Continuity mistake: All the monitors aboard Discovery-1 are standard CRT screens of 1980s vintage (curved face), yet in "2001", they were all flat screens. and there's been no upgrading between the events of the two films.
Continuity mistake: At the end of the film the hero follows the bad guy into a reservoir. When he gets there, the bad guy has dug a very deep hole in the ground in which he wants to bury the girl. But the bad guy arrived only two minutes or so before the hero and didn't have the time to dig a hole of that size.