Audio problem: Despite the fortress being made of stone, when the Hammer Bros. hit one of its bricks, it makes the sound of metal. (00:06:42)
The Koopas are Coming! The Koopas are Coming! - S1-E35
Continuity mistake: When Mario says that he and his friends can attack Redcoat Koopa from behind, his head is layered behind the bubble he is in. (00:11:59)
The Koopas are Coming! The Koopas are Coming! - S1-E35
Revealing mistake: When George Washingtoad slides away from his tent, he briefly overlaps the stove and one of his guards. (00:07:20)
The Koopas are Coming! The Koopas are Coming! - S1-E35
Continuity mistake: When Mario cools himself down in the bucket of water, there is no puddle nearby, but when he carries Luigi over to the stove, one appears. (00:06:59)
The Koopas are Coming! The Koopas are Coming! - S1-E35
Continuity mistake: When Mario jumps into the bucket of water, his left arm changes from blue to skin colour. (00:06:31)
Continuity mistake: After Toad says that he and his friends are surrounded, the white spikes on El Koopitan's tail turn orange. (00:12:04)
Revealing mistake: When Mario says that it does not look good for him and his friends, a Koopa Troopa's foot overlaps the sombrero chariot. (00:06:46)
Continuity mistake: When Zero walks up to Princess Toadstool after fighting the Koopa Troopas, the bathtub's levers and showerhead disappear. In the same shot, Princess Toadstool's brooch changes from being yellow with a blue centre to blue with a yellow centre. (00:07:30)
Revealing mistake: In the live-action segment, when E.C. arrives, the basement shakes but the objects remain stationary, revealing that the shaking was achieved by shaking the camera. (00:02:10)
Continuity mistake: When El Koopitan throws some cacti at Zero, the green rings around the spikes on his shell turn orange, like the spikes themselves. (00:08:51)
Revealing mistake: When Rappin' Koopa looks through his telescope, part of the background can be seen at the edges of the screen. (00:05:08)
Continuity mistake: Throughout the episode, Koopa Troopa's green hands turn yellow several times.
Mario and the Red Baron Koopa - S1-E30
Continuity mistake: When the Lakitu starts throwing Spiny Eggs at the Mushroomers, its green snout turns yellow, like its goggles. (00:04:59)
Mario and the Red Baron Koopa - S1-E30
Audio problem: When King Koopa says that unless the Mushroomers surrender to him, he will bury Pastaland with snow, his mouth does not move. (00:06:04)
20,000 Koopas Under the Sea - S1-E26
Revealing mistake: When Mario and his friends are running from the Koopilus, Mario freezes for a split-second. (00:03:43)
Hooded Robin and His Mario Men - S1-E25
Continuity mistake: When Mario and his friends look at the hallway leading to the Coins, Hooded Robin's red wings turn yellow. This also happens when Princess Toadstool takes a curtain. (00:11:19 - 00:11:47)
Hooded Robin and His Mario Men - S1-E25
Continuity mistake: When Princess Toadstool takes a curtain, Hooded Robin's red head turns yellow, like his beak. (00:11:47)
Hooded Robin and His Mario Men - S1-E25
Revealing mistake: When Mario tells Hooded Robin to remember him and his friends, Luigi is layered between the crossing gate. (00:07:04)
Hooded Robin and His Mario Men - S1-E25
Revealing mistake: When Hooded Robin introduces himself, a bush moves with the screen for a few frames. (00:04:06)
Hooded Robin and His Mario Men - S1-E25
Continuity mistake: When some Koopa Troopas surround Mario and his friends after they are caught in a net, they have blue hoods. But when one of them mistakes them for Hooded Robin, their hoods turn green like their bodies. This also happens when they are told to retreat. (00:03:19)