Continuity mistake: When the ketchup lorry crosses the bridge, it has a cream cab and a red trailer, but in the next shot, it has a blue cab and a grey trailer.
Revealing mistake: When the camera pans across the front of Double Cross Ranch, the edge of an animation cel is visible. (00:13:51)
Revealing mistake: When a front view of King Koopa running down a street is shown, he clips through a building. (00:15:25)
The Koopas are Coming! The Koopas are Coming! - S1-E35
Continuity mistake: Just before the pillory is destroyed, it is violet, but in the next shot, it is orange. (00:14:37)
Audio problem: When King Koopa throws the snake at the Mario Bros., they use Luigi's voice when King Koopa says "Quick, quick! Run away from him!"
Revealing mistake: When the camera scrolls to Grunt (in the scene where the gang are locked up in a cell, being watched a strong, non-human security guard named Grunt), he appears out of thin air. The animators might have had some trouble putting him into the scrolling shot. (00:11:15)
Character mistake: When the Koopas chase Mario and Luigi, the sign says "COOPA ISLAND" instead of "KOOPA ISLAND." (00:06:39)
Character mistake: When Koopa is chased by a cop, he passes a Burger Shop. The sign says "BURCER SHOR" instead of "BURGER SHOP." (00:04:35)
Character mistake: The title card says "Plummers Academy" instead of "Plumbers Academy."
Mario meets Koop-Zilla - S1-E28
Continuity mistake: When Mario is eating sushi, he eats it with a fork, but his fork disappears and a spoon appears out of nowhere.
Mario meets Koop-Zilla - S1-E28
Continuity mistake: After when Luigi says "It's an earth shake!" when he flips, his straw hat changes into his green cap in mid-sentence. (00:03:58)
King Mario of Cramalot - S1-E2
Audio problem: At the end, when everyone is laughing, Toad's mouth isn't moving. (00:18:43)
King Mario of Cramalot - S1-E2
Revealing mistake: When king Koopa says "I don't know. What?", his spikes disappear. (00:15:56)
King Mario of Cramalot - S1-E2
Audio problem: When Toad says "that was close", his mouth isn't moving. (00:11:29)
Other mistake: In the theme song, there's a part where Mario touches a star and gets fire power. The star is suppose to give hyper power, it's suppose to be a flower to give him fire power.
Robo Koopa - S1-E52
Continuity mistake: At one point, Mario asks Dr. Nerdnik how to stop Robo Koopa. The doctor walks in circles, and in the next shot, he is in a different position. (00:06:40)
