Continuity mistake: Prior to bringing Ray up for the role-playing exercise, the parenting teacher erases a circled phrase from the chalkboard. Throughout the scene, the chalked circle flips several several times between being totally erased and having a faint outline left over.
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.
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.
Plot hole: When Hulk and Banner have been physically separated by the nutrient bath, they are both wearing tattered pants. Given that Hulk and Banner were previously occupying the same body, this should not be possible. Hulk was the one that went into the nutrient bath, so if Banner's body was separated from Hulk, then Banner should be naked.
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.
Other mistake: Season 2 episode 13 "Monkey Fun": Just before the enlarged Titano appears at the zoo, there is a family watching normal-sized monkeys in a cage. The family father (farthest on the right) has a drawing disorder with his eyes: their pupils look up and down, respectively, giving him a rather goofy expression.
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.