The New Kid - S1-E2
Other mistake: At the start when the gang change the time on the clock in the classroom, it wouldn't control the main school clock, plus in every other episode the clock has been operated by The Box on the side of the school, as shown in " The spy who came into the playground".
Other mistake: At lunch, when the kid tells the gang that Spinelli's parents will be the first parents on the space shuttle, Gus's right elbow vanishes, then reappears mid-shot. (00:02:42)
Other mistake: At Parents' Night at the school, when Gretchen's parents walk into Miss Grotke's classroom, Gretchen's father clips through the door. (00:05:46)
Other mistake: When Spinelli's real parents arrive at Parents' Night, the shot is flipped: the potted plant and poster are on the opposite sides, the letter on the poster is mirrored, the door opens the opposite way, and Spinelli's parents are running in the wrong direction. (00:08:26)
Other mistake: When Spinelli's real parents arrive at Parents' Night, as Spinelli's mother tells Miss Grotke, "She just stopped wetting the bed this year," her necklace vanishes, then reappears mid-shot. (00:09:23)
I Will Kick No More Forever - S1-E11
Other mistake: When the gang goes to visit Vince in his house, it shows Vince watching a video of a kickball game. But kids most definitely wouldn't be able to bring a video camera into school, and it most probably would be confiscated by Miss Finster.
Other mistake: In the episode, "the peanut butter kid", he is always eating his sandwich and it always seems like he only took a bite out of it and sometimes it went all the way back to the top. How could that be, he couldn't be chewing the entire time.
The Great Jungle Gym Stand Off - S1-E21
Other mistake: When TJ says that he and the rest of the gang met at old rusty, it shows you a flashback and the kindergartners are wild, but they only became wild when Gus arrives later (as said in All Growed Down).
Suggested correction: It's not true. After Gus "changed" the kindergartners he was sent away from school.
This correction misses the point of the mistake. In "Recess: All Growed Down," when Gus moves to the school, the kindergartners are shown as "normal," but then Gus changes them to be wild, and they start to have torn clothes and paint on them. However, in the flashback scene in this episode, it shows the gang meeting on the first day (excluding Gus), and they have torn clothes and paint on them. This doesn't make sense because they only became that way when Gus moved to the school.