Continuity mistake: In the beginning, as Gus' dad walks away, the A/C duct goes way down the hallway, and one side is halfway in one tile and the other side is halfway on another tile. When Gus is talking, the duct is much shorter, and the whole duct is contained in one tile.
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".
Add timecameron davies
Continuity mistake: In the beginning, right as Mrs. Grotke asks for Gus to describe his "personal journey", there is a short kid with a white t-shirt and dirty blonde hair, with the globe behind his head. As the kid asks if they can go to recess now, the globe has moved way to the left.