Continuity mistake: In the episode when it's Kenan's birthday, Kenan and Kel are looking for Kenan's present in Kenan's parents room. As they're searching, Kel throws some of Kenan's parent's clothes all over the place. But then when Kel throws the snowglobe, there is practically no mess, but just a few clothes on the floor - less than before. Some clothes on the bed disappear as well.
Revealing mistake: During the scene when Mr. Lyle is talking to the General (butcher character), his glove that he wears on his hand is removed to make a point about his thumb having been cut off. In the next shot, we see Mr. Lyle walking around the desk and putting his glove back on, and you can see his thumb folded under his hand as if the actor was trying to hide it and did not realize it could been seen from the camera angle.
Other mistake: In this episode, the Spellmens and Salem are sitting at the breakfast table. You can see Sabrina has a stack of pancakes in front of her. But in the episode Pancake Madness, they are forbidden in the Spellman home because of the effects that come from them.
Other mistake: At the start of chapter 12 in the episode "Kingdom Come," Frank returns home via taxi. In front of his house in Seattle, WA, there is a blonde woman walking a Rottweiler dog. This same blonde and Rottweiler can be seen walking by the crime scene in San Francisco in the "Gehenna" episode.
Continuity mistake: In Episode 5, "Live Hard, Die Young and Leave A Good Looking Corpse": As Lillie is preparing to cut Zane's throat with her fingernail, she stands with her hand raised above her head for a while. When seen from the front, her hand is balled into a fist with the index finger extended, but when seen from the back all her fingers are extended. The view alternates like this several times, and each time the hand varies between fist and outstretched fingers.
Factual error: When the Hulk jumps up and grabs on to the tail of the helicopter, he is somehow able to hang on to the tail while spinning the helicopter in a circle. Helicopters require a certain weight distribution in order to maintain stabilized flight. Someone of the Hulk's size and strength wouldn't be able to just hang on to the tail and spin the helicopter. He instead would bring the helicopter crashing down.
Factual error: Season 2 episode 10 "Double Dose": When Superman snatches Parasite's escape boat and hauls it back to Stryker's, Parasite attempts to blast him with a shotgun found aboard. But somehow the animators appeared unable to decide whether the gun should be a double-barrel or a pump-action type; and building a double-barrel pump gun would be impractical due to additional weight and bulk.
Plot hole: When Nicky goes into prison in Mexico to give a criminal a shot of insulin, two errors are seen. 1) The needle and syringe are far too big for an insulin shot, which takes a one ml syringe and a small sub-cutaneous needle. 2) When we first see the syringe, there is a small amount of insulin in it, but it grows the more times we see it, until a large syringe is two-thirds full - insulin is enough in a one ml syringe.