Contents of Kid Icarus' arrow quiver when the Sheriff steals Kid's buzz saw arrow in Misadventures in Robin Hood Woods.
In Misadventures in Robin Hood Woods, Kid Icarus is introduced as "Kid Icarus of Olympus." Mount Olympus was his home in the video games and the comic books, but in the TV show Captain N universe, in earlier seasons, his home was always called Mount Icarus.
In the episode "Pursuit of the Magic Hoop", Princess Lana wanted to wish her father King Charles back home, but she never considered making that wish when the N team had the magic lamp in the episode "Wishful Thinking".
The path to Mother Brain's lair changes every time our heroes visit Metroid.
In the first season, Donkey Kong and some assorted wildlife are the only lifeforms in Kongoland. In the second season there are blue-skinned villagers.
In the background of the Punch Out gym, "BIG MATCH" is misspelled (as "BIG MATC.")
In the opening of "Kevin In Videoland", Jeffrey Scott's first name is misspelled (as "Jeffery.") (Fixed on DVD)
The Mega Man 2 Robot Leaders (as seen in The Big Game) look nothing like their game counterparts, and their abilities are also different (for instance, Wood Man has a vine whip he doesn't have in the game.)
In Mr. And Mrs. Mother Brain, the arrow maker makes a "cow" appear with his cow arrow, but it has horns. Cows DO NOT have horns. "Bull arrow" would have been a better name for this contraption.
In two frames during Germ Wars, Kevin's life force is colored as the normal Kevin is.
In Gameboy, Simon can be seen in one of the "corridors of Metroid" scenes prior to him actually arriving on Metroid.
In Simon the Ape-Man, the establishing shot of the Palace of Power is upside down.
At the end of "Mega Trouble For Megaland", when the N Team talks to Mother Brain, Lana's shoulder pads are drawn pink (they're supposed to be white.)
When Eggplant Wizard is awakened in "The Most Dangerous Game Master", his lips are brown.
King Hippo is blue-skinned on the show, but has a normal flesh color in the game Punch Out.
In some of Kevin's flashbacks in "The Most Dangerous Game Master", he is drawn with his Zapper belt. But these are pre-video land Earth flashbacks. He didn't have his power weapons then.
When Eggplant Wizard says "please don't hurt me!" in "Having a Ball", his lips don't move.
During the intro, when Mother Brain says "Mother Brain will get you, little princess!" her lips don't move.
In "In Search Of The King", the gateway in the Mirror World that leads into and out of the world looks entirely different on the coming visit than on the going visit.
In 7 different screen shots there was a goof causing them to not have a background.
In "Gameboy", everyone is traveling through the corridors of Metroid to reach Mother Brain's lair. If they're in the confines of Metroid, how did Lana end up outdoors somewhere?
In Misadventures In Robin Hood's Woods, Kevin and Kid Icarus fill up their Warp Wagon in Nottingham. Why would a medieval world have a fuel pump for a futuristic flying machine?
Mother Brain banished King Charles to the Mirror World, yet in the Mirror World he has a large picture of Lana on his house wall. Where did he get it? It's not likely Mother Brain let him pack a bag of stuff for his banishment, after all.
In The Most Dangerous Game Master, Dr. Wily builds the body of the Mike Vincent android BEFORE he steals Captain N's memories. How could he know what Mike Vincent looks like without having yet gotten the memories?
In Having A Ball, separating the Triforces nearly kills Princess Zelda. Yet in the Zelda cartoon series she appeared in prior to Captain N, the Triforces are separated for the entire series and she doesn't feel an ounce of pain from it.
Everyone refers to the character of Pit as "Kid Icarus." Kid Icarus is the name of the game he came from, but this character's name is Pit.
In Kevin in Videoland, Kevin says he's played Donkey Kong numerous times, and to trust him with his volcano escape route. In actually, there are no volcanoes in Donkey Kong, so this doesn't make sense.
At the end of Gameboy, Kevin says the hat they give Gameboy was "made especially for him", but it has one-size-fits-all adjustments.
Dr. Wily's swamp creature in How's Bayou was programmed with one purpose, to destroy Captain N - Wily even says this himself. Yet the creature also goes after Lana and Simon, who it was presumably NOT programmed to go after.
In "Gameboy", Simon asks what's for lunch, even though it's been established that it's dark outside.