Visible crew/equipment: When Freddy falls over the banister onto the stairs near the end, notice the crash mat he lands on. (01:18:55)
Factual error: While the Leonov has a centrifugal section to simulate gravity, the ship's bridge is not part of it (evidenced by the stationary views outside its portholes). Yet in various scenes, including the one when Floyd rushes in to discuss his plan to return to Earth sooner with Tanya, gravity seems quite evident. Floyd marches across the compartment onto the raised pilot area's floor, then steps down from it, his foot landing audibly. Tanya's open jacket also hangs down normally as she moves about. Yet when Floyd demonstrates his plan using two pens, they float in mid air. (01:26:50)
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.
Revealing mistake: Near the end, Clint Eastwood picks up a lamp in anger and throws it across the room, but there's no power cord attached to the lamp.