Continuity mistake: When King Koopa tells Fryguy to prepare the Lava Machine, the white spikes on his tail turn orange. This also occurs when he approaches the boat. (00:10:06 - 00:14:50)
Koopenstein - S1-E21
Continuity mistake: In Mouser's first appearance, he does not have a laboratory coat on, but in the next shot, one appears. (00:03:46)
Two Plumbers and a Baby - S1-E17
Continuity mistake: When Mario says that they have to free the children, his black sideburns turn red, like his cap. (00:06:43)
Two Plumbers and a Baby - S1-E17
Continuity mistake: Normally, the castle has a door, but when King Koopa says that the infants will have to do all of his chores, the door disappears. This also happens when Luigi is trying to listen in on what is happening inside the castle. (00:06:05 - 00:06:27)
Continuity mistake: After Princess Toadstool is captured by Blackbeard Koopa, the Koopa Troopa holding her left arm has a blue bandanna. But when Blackbeard Koopa says that she did not come willingly, the bandanna turns red. (00:07:53)
Continuity mistake: When Captain Clump says that Blackbeard Koopa bothers pirates, his purple trousers turn red. (00:07:59)
Continuity mistake: When the Mario Bros. are revealed, Mario is wearing the tank top of his disguise, but in the next shot, he is wearing his normal clothes. (00:15:18)
Continuity mistake: Normally, Blackbeard Koopa's ship is blue, but when Princess Toadstool is on his ship, it turns brown like Captain Clump's. This also happens when it is docked at his fortress. (00:08:29 - 00:11:17)
Continuity mistake: When Butterfingers urges Princess Toadstool to stay, her leg bracelet disappears. This also happens when they run away from King Koopa. (00:12:14 - 00:14:34)
Continuity mistake: Throughout its appearance, the grey sideskirts on Mario and his friends' car turn brown like the rest of the car several times. (00:03:44 - 00:09:06)
Continuity mistake: Throughout the episode, the white spikes on King Koopa's tail are coloured orange instead.
Continuity mistake: When Mario and his friends look at Koopa Khan while on the bridge, Princess Toadstool does not have a cape. But when she and her friends fall after Koopa Khan destroys the bridge, one appears. (00:10:49)
Continuity mistake: When Drainotto says that he could make an underground river with some help, the number of fingers he has on each hand changes from five to four. (00:07:46)
Continuity mistake: When Toad puts his cap back on, his torso changes from skin-colour to blue, while his trousers change from blue to skin-colour for a few frames. (00:04:59)
Continuity mistake: When Moon Man Koopa first appears, he has no wristbands, but when he activates a magnet, some appear. (00:08:10)
Continuity mistake: After Princess Toadstool says that King Koopa tricked the Mario Bros, King Koopa's yellow eyes turn white. This also happens after Toad says that the Mario Bros. are safe. (00:09:39 - 00:10:18)
Continuity mistake: When King Koopa first appears, he has two Koopa Troopas with yellow underbellies. But when Princess Toadstool says that he tricked the Mario Bros, one of the Koopa Troopa's underbellies turns purple. (00:09:34)
Continuity mistake: When the Mario Bros. pass King Koopa's minions after surviving the first trap, the lenses on Mouser's glasses disappear. (00:11:49)
Love 'Em and Leave 'Em - S1-E8
Continuity mistake: When Queen Rotunda says she will never find the perfect desert for Prince Pompadour, the yellow trims on her dress turn blue. This also happens when she says that Mario's ice cream looks delicious. (00:08:19 - 00:09:05)
Love 'Em and Leave 'Em - S1-E8
Continuity mistake: When Princess Toadstool says that she and her friends are breaking out of the dungeon, the number of fingers Luigi has on each hand switches from five to four. (00:11:49)
