The Crab with the Golden Claws: Part 1 - S1-E1
Continuity mistake: Tintin is locked in a room tied up to two pipes. There is rope around his torso and ankles which is connected to the pipes above and even his arms are tied up, connected to the pipes behind him. Allan then enters the room and the rope that was connecting his arms to the pipe is now nowhere in sight. It is partially visible for a few frames, but then vanishes for the rest of the shot. Then when the shot cuts to Tintin, there is suddenly rope wrapped all around the pipe behind him. (00:12:35)
Bug Off/The Crawl Space - S9-E5
Continuity mistake: In Moving Away, Tommy tells the other Rugrats how they first met when Angelica lied about the nasty things they did. However in the Crawl Space, there is a flashback of Tommy, Chuckie, Phil and Lil playing in the playpen when they were younger. Chuckie is scared of the Jack-in-a-box in that flashback, so the Rugrats could not have met for the first time back then.
Continuity mistake: When Marshall first finds Trip's letter, he holds it from the left side. In the close-up, he's holding it from the right side. (00:02:10)