When the movie starts, John has short hair. When he wakes up after being "brain dead" for 4 months, his hair has grown way too much; about a year's worth.
After Maddox's lower midsection is obliterated by the turret, he continues to stand upright for many moments before turning and falling off the duct pipe. But with no spine, that part of his torso could not have remained fully upright.
While D-Day was typing on ZED's keyboard he types a command that results in a 'Access Denied' result. Upon his second attempt, he logs in as "POE" with a password of "CRIME DOES NOT PAY". This would result in a system error, as passwords back in those days could not accept a "SPACE" within the password character space, as well as such a sophisticated system would require a far more complex password for such an investment as ZED to prevent unauthorized use.
When Brennick uses the shovel to sever a drone's arm, the part of the shovel's blade that has been cut out to fit the stunt person's arm is visible.
They had so many equipment and advanced technology in place in prison that they could even capture and see the dreams of a prisoner. But they didn't have a simple CCTV camera that would have shown to them that 187 was trying to sexually assault Gomez, so it was he who was the perpetrator, instead of putting all three in laser cage where they can tell lie for various reasons, a Brennick eventually did. They should have used the camera to prevent such sexual assault from starting in the first place.
John had an encounter with police dogs who bite her body at several places. After he reaches prion, none of the bite marks or wounds is visible... unless it so much time from getting nabbed to getting sentenced, that the wounds healed.
When Loryn goes to warn John that he needs to cooperate (when he is the torture room strapped to the harness) she is escorted out of the room. When she does that she is clearly crossing the yellow line that would trigger pain in the prisoners.
Why would they need to bring that additional complex device to shoot and kill Moddox? They already had intenstiner put in the bodies of all prisoners that can cause pain and even death.
Karen couldn't hide her magnetic vest that conceal her pregnancy from the security scanners. That was even after John has clearly told that. That was shabby of Karen that she was responsible for both of them getting nabbed and sentenced.