Miscellaneous: During a fight in deep space, O'Niel's spacesuit sleeve detaches itself from the glove.
Factual errors: Bodies do not explode when exposed to a vacuum (except in cases of explosive decompression, which did not occur in this film).
Plot holes: Concerning the incident where the worker descends in the depressurizing elevator, without a full pressure suit - surely there would be a manual override for the elevator controls, or an Emergency Power Off button to press, in order to save him!
Audio/visual unsynchronized: Spota talking in the zero-G cell.
Continuity: Several times during the first half hour of the movie, O'Niel's uniform name tag changes spelling from "O'Niel" to "O'Neil" and back again.
Factual errors: In the opening sequence where "computer readouts" across the bottom of the screen set the scene, one of the last of these identifies the Io mine's "Principle Ore: Titanium" instead of "principal". Also "marshal" is misspelled as "marshall" (but "dependants" is the usual UK English spelling of "dependents" and is not an error).
Factual errors: In the opening scenes in the mining levels, human voices are heard through the radio links, but ambient industrial noise is heard "in the clear". In a vacuum there would be no such noise. If the noise were heard from the miners' perspective (as was the radio chatter) it would have been low frequency noise from mechanical contact with the ground and manual equipment only.
Factual errors: The shuttle carrying the two hit-men arrives more than an hour early on its 70-hour trip from the space station. Since the laws of physics couldn't have been broken, this means that someone made a huge error in calculating the orbit of the shuttle (all objects in this case are in orbit of Jupiter), but by blind luck still managed to intersect with Io anyhow. If the shuttle HAD arrived on time, Io would have been in a totally different position, as it moves at 17.3 km per second due to its low orbit around Jupiter. The only way to arrive early would be to expend a lot more energy, which would mean lost money for Con-Am. (Even then you would still know the exact time of arrival - it's just physics.)
Revealing mistakes: When O'Neil draws blood from Segan's neck the blood is a clear red when it should be opaque.
Boom mic visible: During the chase scene in the tunnels, for a few frames the boom mic pops into the view in the bottom right corner.