Let's face it: the TV shows aren't perfect. There are a lot of errors. In this section, I'll list all the errors that I can find (and try to explain some of them away).
Continuity error: The moblin says "Hold this while I get the Triforce." But he doesn't hand his spear to the other moblin. Perhaps Len Carlson was supposed to say "him" (Link), rather than "this". (Explanation: The moblin has so little respect for Link, he refers to him as a thing, rather than a person.) Found by Kelly Harris.
In the same scene, the spear turns into a staff. Found by Kelly Harris.
Spryte perches herself on Link's left shoulder, then, after the commercial break, she's on Link's right shoulder. (Explanation: She switched shoulders, because she likes Link's right shoulder better.) Found by Kelly Harris.
Link says of Ganon: "And he's getting away. We'll never catch him now!" But neither he nor Zelda are making any attempt to go after him. Found by Kelly Harris.
When Link says "My kind of girl", his lips don't move. (Explanation: Link is practicing his vantriliquism.) Found by Kelly Harris.
Continuity error: When Link says "I'll just slow him down a little", he pulls out his sword, but he wasn't shown putting it away earlier. Found by Kelly Harris.
Zelda's accent sounds British at some points, rather than the usual American or Canadian.
Continuity error: Zelda asks Link: "And aren't you supposed to be cleaning the kitchen?" However, Zelda didn't tell Link earlier in the episode to clean the kitchen, nor is Link shown cleaning the kitchen. (Explanation: She just wants to get Link away from her.) Found by Kelly Harris.
When Spryte is explaining to Zelda what happened, her dress is strapless, rather than its normal sleeveless. It later changes back to sleeveless. Found by Kelly Harris.
The Missing Link
When Zelda gets out of Link's way, Link lands with an audible thump. How can a spirit make a thump? Found by Kelly Harris.
Kevin In Videoland
During the first shot of Kevin's TV screen when he's playing "Punch-Out!!", the energy bars and stats are missing. (Explanation: The game is like that on Kevin's Earth. They appear and disappear.)
During the first two shots of Kevin's TV screen, there's no brand name. When Duke jumps in, the word SONY is visible on the set.
Kevin's jacket is red on Earth but orange in Videoland. (Explanation: That is the way that his jacket is "translated" from Earth to Videoland.)
Kevin's sneakers are white on Earth but white and black in Videoland. (Explanation: That is the way that his sneakers are "translated" from Earth to Videoland.)
When Kevin arrived in Videoland, he wasn't scared at being animated. (Explanation: He was too scared at being in an unfamiliar place instead.)
When looking at the map, Simon points at an "M", and Kevin points at an "I". Then Simon points at an "E", and Kevin points a bit away from the "I". (Explanation: They change their minds.)
The "M" on the map changes to a "P" or an "R".
Lana is brought from Mother Brain's lair to the tower via a chute. However, the same trap door in the tower later takes the N Team to the corridors of Metroid. It should take them to Mother Brain's lair. (Explanation: The chute can be redirected somehow, or there are branches in the chute.)
Just before falling through the trap door into the corridors of Metroid, Lana's boots are pink with green stripes, rather than blue with yellow stripes.
While care is taken in illustrating how much energy that Kevin uses up (care that is not taken in other episodes), he is able to fire off a few more shots in the corridors of Metroid than he should've been able to prior to running out of power.
Right before the N Team leaves Metroid, the shoulders of Lana's shirt are pink, rather than white.
How's Bayou (version 2)
Continuity error: Kevin is shown playing Bayou Billy just before getting pulled into Videoland. He was shown playing "Punch-Out!!" in "Kevin In Videoland". (Explanation: This error is the result of replacing the live-action footage of Kevin used in version 1 with the live-action footage used in "Kevin In Videoland". I ignore the footage used in version 2.)
Kevin's Bayou Billy game looks nothing like "The Adventures of Bayou Billy". (Explanation: The game is different on Kevin's Earth.)
The Most Dangerous Game Master
Dr. Wily already had the android's body built before getting Kevin's memories of Mike Vincent. How could Dr. Wily know about Mike beforehand? (Explanation: Dr. Wily is psychic.)
In Kevin's first memory sequence, Mike is wearing a belt with a Power Pad and Zapper. How could that be if it's an Earth memory? (Explanation: Mike made the belt and wore it to scare Kevin.)
In Kevin's first memory sequence, Kevin is wearing a belt with a Power Pad and Zapper. How could that be if it's an Earth memory? (Explanation: Kevin made a belt like that, because he thinks it looks cool. It's not the same belt that he wears in Videoland.)
During the race through Castlevania, when Mike sees the huge soldier, he yells "Hey!" in Kevin's voice. (Explanation: The android can immitate Kevin's voice.)
Both of Kevin's memory sequences are animated. If they're on Earth, they should be live-action instead.
When Simon flexes his muscles the first time, his coat is light blue, rather than dark blue.
Mega Trouble For Megaland
When Kevin and Lana call Mother Brain at the end of the episode, the shoulders on Lana's shirt are pink, rather than white.
When Lana wakes up in bed, she's wearing her nightgown. But, when Lana hops out of bed, she's wearing her robe. (Explanation: Lana sleeps with her robe and quickly threw it on.)
Mega Man wears pajamas?!
When Kevin decides they better go down to the vault, the N Team members are wearing their pajamas. When they arrive at the vault, they're wearing their day clothes. (Explanation: The N Team was in no hurry to get to the vault and stopped off to change their clothes. However, how did Lana change her clothes, if she left her room? Either she went back to her room to change her clothes, or she keeps her clothes in someone else's room!)
Simon wishes his nose to be straighter, but then it's suddenly back to normal.
On two occasions, Kevin jumps really high without pressing any buttons on his Power Pad, yet he clearly says he's using it.
Before Kid Icarus' wish for everything to be back to normal takes effect, the other N Team members are colored normally, rather than as gold trophies.
Three Men and a Dragon
In one of the shots during the Three Keepers' call to the Palace, Kevin's jacket is all orange.
The audio lags behind the animation at a few points.
Nightmare On Mother Brain's Street
When Kevin sees his bedroom in the Nightmare Zone, he thinks he's home, even though he and the bedroom are still animated. (Explanation: Kevin's not very bright.)
When Kevin says "A Plus, Mother Brain!" near the end of the episode, the "N" on his jacket is missing.
Simon the Ape-Man
When Simon speaks after exiting the warp and landing on the floor in the Palace, his coat is light blue, rather than dark blue.
When Simon walks off as a tour guide, the "N" on Kevin's jacket is missing.
In Search of the King
When Lana is sitting in front of her mirror at the beginning of the episode, she is wearing her crown, earrings, and nightgown, and she is barefoot. When she is standing in front of the mirror a few seconds later, she is wearing her boots. When she is shown from the side, placing her hands on her mirror, she is wearing her full dress clothes.
When Lana wakes Kevin up in his bedroom, she is barefoot and wearing a pink robe. When Simon wakes up, Lana is wearing her boots.
Kevin is wearing blue pajamas when Lana wakes him up. Lana tells him to get dressed. When Simon wakes up a few seconds later, Kevin is fully-dressed and just finishing putting on his jacket. (Explanation: Kevin quickly stripped in front of Lana and Simon and got dressed really fast!)
When King Charles' Mirror Image Opposite speaks for the first few times, he sounds like King Charles. But, when he frees the other Opposites from the Mirror World, his voice changes for the rest of the episode. (Explanation: He thinks his real voice is much cooler, but he didn't want the real N Team to be awe-struck at his cool voice, so he used a fake voice until they were in the Mirror World.)
When Kevin draws his Zapper and points it at Mirror Mega Man and Kid Icarus, his Zapper is gray.
When the elastic arrow surrounds the Mirror N Team, the shoulders on Mirror Lana's shirt are pink, rather than white.
When the elastic arrow surrounds the Mirror N Team, Mirror Lana's left boot suddenly changes in plain sight from blue and yellow to pink and yellow.
Metroid Sweet Metroid
When the warp to Metroid opens, Kevin sees his neighborhood. He walks into the warp with Duke. Everything is fine as he walks down the street. It takes a metal tree for Kevin to realize that something weird is going on. It is only then that he realizes that they're still animated. Why didn't Kevin realize that his "neighborhood" is animated before he walked into the warp? (Explanation: Kevin's not very bright.)
When Lana bends over to pick up Kevin's Power Pad and Zapper, it looks like she's not wearing any underwear. (Explanation: Lana doesn't wear underwear. Why that is, I'll leave up to you.)
Simon asks what's for lunch while it's still dark outside.
Queen of the Apes
The brain swapper not only switches people's minds but their voices as well. This is common in comedies involving mind-switching. (Explanation: The brain swapper teleports people's vocal chords.)
Some of Gameboy's circuitry is sent to Mother Brain's body for some odd reason, which makes me wonder how Gameboy's body is still able to function.
Quest For the Potion of Power
Continuity error: Link pulls out his sword to smash the glass, and then he pulls it out again to fight Horsehead, even though he wasn't shown putting his sword away after breaking the glass. (Explanation: He put it away while Horsehead was arriving.) Found by Kelly Harris.
Judging by the way that Link jumps to attack Horsehead, he was going for the head, but Kevin tells him about the head later, and Link admits that he forgot. (Explanation: Link was only sarcastic about forgetting.) Found by Kelly Harris.
The Trouble With Tetris
Some shots are blurry in the episode.
When Lyle kisses Lana's hand, Lana's missing her eyebrows.
When Kevin and Lana are running side-by-side, Lana's missing her eye pupils.
The Big Game
Mega Man builds a skateboard for Kevin, but Kevin already had a skateboard in "Simon the Ape-Man". (Explanation: Kevin's first skateboard broke.)
Lana is bad at riding a skateboard, but she had asked Kevin to teach her in "Simon the Ape-Man". (Explanation: Kevin didn't teach her.)
After Simon turns on the TV, there are two shots of the group sitting on the couch that are really messed up! Two Lanas are shown (one sitting upright and one lying down), and two Simons are shown (one lying down, and another lying down behind him)!
Right before the N Team arrives on California Games, other people are shown on the beach. But these other people are gone for the rest of the episode. (Explanation: These people are bad guys, and they left in fear when they saw the N Team.)
When Rick, Stacey, Romeo, and the huge kid are warped to Videoland, they don't seem surprised at being animated. Rick's only confused at being at the beach. (Explanation: Three jocks and a blonde valley girl. Need I say more?)
"NORTH RIDGE" is written on the gym building, which is incorrect. Northridge is one word, not two. Oddly, when Rick says "Yo, this better not be some kind of joke!", the "H" and "R" are close together.
When Kevin and Lana gasp, the shoulders of Lana's shirt are pink, rather than white.
Continuity error: Lana says "Hey, we asked for the best from your world, and the Ultimate Warp Zone chose Kevin as our Game Master!" This is inconsistent with "Kevin In Videoland", which shows that the N Team didn't ask for anyone at all. (Explanation: Lana was more concerned with giving a good speech than with accuracy.)
Continuity error: Lana tells Kevin that his friends will forget about Videoland when they go back to Earth and that Kevin would also forget when he went back. This is inconsistent with version 1 of "How's Bayou", where Kevin suggests that he and Lana go to Earth, and she replies "Some other time, Kevin." Besides, how does Lana know that Wily's Warp Zone Shifter will erase memories just like the Ultimate Warp Zone? (Explanation: Lana was lying. She just wanted Kevin to think that Stacey would forget about him. She also wanted to scare Kevin into staying in Videoland with her.)
The Lost City of Kongoland
After Simon and Lana land on the ground, Lana takes out the map from somewhere below her chest. Not really a mistake, but it's something to think about. ^_^
When Lana says "They're my favorite kind", and later when she deflects Viroid's blast with Simon's mirror, Kevin's life force is colored as Kevin normally is.