Doug Takes a Hike / Doug Rocks - S1-E4
Continuity mistake: When Roger is dancing in Skeeter's yard, he changes color.
The Blue Lotus: Part 1 - S1-E8
Continuity mistake: The background behind the Maharajah and Tintin changes between shots as they watch his son and Snowy. (00:01:40)
Continuity mistake: When Lemmy falls down from the window and running away from Bowser with Iggy, Iggy's face turns orange. Then later, it turns back to green.
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: After Michael's tooth falls out, the toys go to clean it. When they accidentally squeeze the toothpaste on each other, it finally shows Alfred holding up the toothbrush correctly because Diesel can't seem to, Alfred's appearance is short, dark green and smaller in size. But then Johnson appears and says "I'm going to remove this toothpaste tube before it causes anymore damage" the shot cuts to Alfred with the toothpaste squeezed on him, and his appearance has changed; with a larger head, bright green body and larger in size. A few shots later, he is back to his original form.
Continuity mistake: The episode "Clash Reunion" shows Megavolt in his flashback becoming a supervillain in high school. For one moment he's wearing his trademark goggles, then afterwards they're gone. (00:05:05)