The Alien Costume: Part 1 - S1-E8
Other mistake: After tricking police by disguising himself as a policeman, Spider-Man changes his clothes in the middle of traffic with numerous people around but somehow nobody notices this.
Neogenic Nightmare Chapter 8: Duel of the Hunters - S2-E8
Other mistake: After falling down the cliff and getting blasted back by his van's explosion, the Punisher shows no signs of injury. This kind of fall combined with explosion should have killed him, or at least injure him very severely, as he is a normal human without any superpowers.
Other mistake: Despite being Shield agents the guys shown in the target practice room wear the same uniforms as the guards working for The Kingpin.
Secret Wars, Chapter 3: Doom - S5-E11
Other mistake: This series is in the same continuity as the other Marvel animated series from around the same time - X-Men, The Incredible Hulk, Iron Man, and Fantastic Four - by virtue of each aforementioned show crossing over with at least one of the others. However, in Fantastic Four, Dr. Doom had a German accent, and in this episode he has a Russian accent.
Spider Wars, Chapter 1: I Really, Really Hate Clones - S5-E12
Character mistake: When the group of Spider-Men are breaking into the Kingpin's building through the front door, Octo-Spidey uses a laser to cut a circle in the door and then proceeds to tear the door off its hinges with his robotic arms. Since he was just able to simply tear the door off, there was no need for him to cut the hole in the door in the first place. It's not like he needed to reach through the hole with one of the arms to unlock it from the other side.
Spider Wars, Chapter 2: Farewell Spider-Man - S5-E13
Character mistake: When Stan Lee is asking Spider-Man what he plans to do after saving all of reality, he responds by saying to find the real Mary Jane. Moments later in the final scene, Madame Web tells Spider-Man that she is taking him to find the real Mary Jane, which elicits an incredulous response from Spider-Man, as if he didn't know that was already the plan.
Partners in Danger Chapter 5: Partners - S4-E5
Other mistake: When baby Silvermane is secured to the platform, his arms are long enough to reach inside the restraints. Considering he is physically a baby, the mistake is that the animators either goofed and drew him to be a little older, or that his arms are disproportionately long.
Partners in Danger Chapter 5: Partners - S4-E5
Continuity mistake: When Smythe is discussing his plan with the Silvermanes, his yellow eyes are blue in one shot.
Sins of the Fathers Chapter 11: Carnage - S3-E12
Continuity mistake: When Carnage escapes from prison a shot of venom escaping is used before changing back.
The Alien Costume: Part 1 - S1-E8
Audio problem: When the field reporter is saying "The shuttle is headed for the greater metropolitan area," his mouth movement does not match the word "metropolitan." (00:04:15)
The Alien Costume: Part 1 - S1-E8
Audio problem: When Eddie Brock is complaining about being stuck in traffic, he hits both of his fists against the handle of his car's steering wheel and somehow the horn blows. (00:03:00)
The Alien Costume: Part 1 - S1-E8
Audio problem: When John Jameson is inside the crater, his mouth is not moving for any of his dialogue. He's communicating with the other astronaut, so it can't be an inner monologue. (00:01:05)
Continuity mistake: When Peter and Debra are approaching Dr. Connors' office, the nameplate on his door misspells his name as "DR. CURT CONNeRS". After they have entered the lab, the nameplate is shown to have the correct spelling. (00:06:10)
Deliberate mistake: When the sewer worker is trying to escape the Lizard, the fast lanes in both directions of traffic are visibly clear for several blocks, which is extremely unlikely in downtown New York. (00:01:10)
Sins of the Fathers Chapter 1: Doctor Strange - S3-E1
Continuity mistake: After Spider-Man, Mary Jane, Dr. Strange and Wong escape from Baron Mordo's lair, the lair itself disappears into thin air because of, according to Wong, the fluctuation of diminishing portal energy. When Spider-Man is saying farewell to Dr. Strange, the lair is there again. (00:18:30 - 00:19:05)
Neogenic Nightmare Chapter 5: Mutants Revenge - S2-E5
Continuity mistake: When Gambit waves to Beast after catching Genevieve, his gloves are missing. (00:16:55)
Neogenic Nightmare Chapter 5: Mutants Revenge - S2-E5
Audio problem: When Wolverine says "I'm tired of being diplomatic," his mouth is closed for the word "being." (00:02:00)
Neogenic Nightmare Chapter 4: The Mutant Agenda - S2-E4
Audio problem: When Hobgoblin says "I don't want to hurt him," his mouth stays open at the end of the line. It's not possible to say "him" without pressing your lips together. (00:17:40)
Neogenic Nightmare Chapter 4: The Mutant Agenda - S2-E4
Audio problem: When Spider-Man is saying to Beast "I'm not sure I still am," Beast is the one mouthing the last three words in the line. (00:09:25)
Neogenic Nightmare Chapter 4: The Mutant Agenda - S2-E4
Continuity mistake: When Professor X is explaining his line of work to Spider-Man, the neck portion of Gambit's headgear is flesh-colored. (00:04:35)
Suggested correction: It was a part of the character's redesign. The writer of Spider-Man, John Semper Jr, disliked the Fantastic Four cartoon to the point that he not only changed characters' designs but their voice actors as well.
Redesigning the character is not a valid correction, because it still creates a contradiction within the shared universe. Even under the pretense of redesigning the character due to not liking the previously established version, it would still be a deliberate mistake.
Phaneron ★