(at around 30 mins) During the battle in the Chemical Weapons storage room, where UniSol Romeo is stalking Luc and reporter Erin Young, Luc starts out wearing a dark jacket over his gray shirt. After a short cutaway from him and Erin, his dark jacket is suddenly gone with no visible sign of it. Later, as the movie returns to the Chemical Weapons room fight after a brief detour, Luc suddenly has his dark jacket back on, but this time we also see him actually take it off after it catches fire.
(at around 1h 11 mins) During the "control room" battle, the regeneration chamber computer flashes "HEALING COMPLETE" during the shot showing the code has been broken - but later, the healing is not yet complete.
(at around 1h 5 mins) After Romeo climbs off the car when Luc kicks him out of the hospital window, a specific pattern of damage is visible on his back (melting of his uniform). He then enters the hospital and rips off his armor and shirt. (at around 1h 16 mins) Later, in Luc and Romeo's final confrontation, Romeo is wearing the same uniform (indicated by the damage on the back) still neatly buttoned/buckled up.
When Luc and SETH looks at the termination code monitor, the Rejuvo-booth program monitor shows "Healing Complete". After Luc kicks SETH away, he runs back to the monitor and it shows "Incomplete"
(at around 1h 12 mins) During the final fight sequence between SETH and Luc, SETH grabs Luc by the neck with his right hand and holds him into the chair. Whilst holding him into the chair, the hand holding the neck switches to his left hand and then back his right hand again between shots.
(at around 48 mins) When the soldiers are setting up the bomb in the generator room. You can clearly see that the bomb is a C-4 bomb. Later, one of the soldiers accidentally shoots the bomb and it explodes. C-4 does not explode when shot. C-4 only explodes when the detonator is triggered.
When SETH is talking to Squid, and his words are captioned on Squid's computer, what he is saying doesn't match what's being typed on the monitor.
Since Devereaux was brought back to life in the first film and then has had his UniSol implants removed prior to this movie making him completely human again, with no ill effects, this means that the government have found a way to bring people back to life normally, yet no one seems to mention this scientific breakthrough.
(at around 43 mins) When the S.E.T.H. brain is implanted into the Super-UniSol, he gives a speech to the rest of the UniSols. During this speech he directs his soldiers to "gather raw materials, so what we may expand our numbers geometrically". Geometrically should have probably been "exponentially".