Here's a collection of miscellaneous information that you may or may not have heard. These are listed in no particular order and will be updated as they come.
In episode 22 ("King Pinned"), a rather bizarre blooper takes place. During the sequence when Spider-Man is swinging after Kingpin's car after having taken Jameson hostage, a commonly-used shot of two polices officers driving in a police car is shown for about half a second. How this managed to get by, I don't know.
In episode 25 ("Menace from the Bottom of the World"), the show starts off using the regular sound heard when Spider-Man shoots his webbing; but from the point where he shoots the giant spider web to trap a vulture bird until the end of the show, the sound heard when he shoots his webbing is a higher-pitched sound.
Most of the animation in episodes 28 ("Phantom from the Depths of Time") and 49 ("Revolt in the Fifth Dimension") come from Krantz Film's Rocket Robin Hood, a show depicting Robin Hood and his merry men in the year 3000. Because of this, "Revolt in the Fifth Dimension" has become the signature episode of the series, being the first episode mentioned by many when bashing the show; and "Phantom from the Depths of Time" has become notorious for it's gaping holes in the plot of the story.
The production company must have really loved the Master Technician and what his ultimate goal was, for they managed to find a way to put him in three episodes making minor changes each time. His first episode was episode 23 ("Swing City") where he was the Master Technician who elevated Manhattan Island into the sky from the Manhattan nuclear power plant.. His next appearance was as Dr. Atlantean in episode 46 ("Up from Nowhere"). Instead of putting Manhattan in the sky, he put it underwater. The inside of Dr. Atlantean's machine used to descend Manhattan island is the same as the Manhattan nuclear power plant. Plus, Dr. Atlantean was the Master Technician with pointy ears, fish scales, and a head fin. His third appearance came in episode 50 ("Specialists and Slaves") where he changed his name again to the Radiation Specialist. Also by this time, he had finally hit puberty, resulting in his much deeper voice; and his goal was the same as the first: raise Manhattan Island into the sky with the nuclear power plant.
Not only did they love using the Master Technician over and over again, they loved using whole episodes with a slightly different plot. In addition to the incidences above. These episodes can be considered "cheater episodes" for overly-reused footage:
-Episode 40A ("The Winged Thing") has large amounts of reused animation from episodes 4A ("The Sky Is Falling"), and 16A, (The Vulture's Prey").
-Episode 40B ("Conner's Reptiles") is almost all animation from episode 2A ("Where Crawls the Lizard").
-Episode 47 ("Rollarama") is a remake of episode 30 ("Vine").
-Episode 48A ("Rhino") is almost completely episodes 8 ("Horn of the Rhino") and 14A ("The Golden Rhino") all over again, including the original dialogue.
-Episode 51 ("Down to Earth") is episode 33 ("Neptune's Nose Cone") all over again.
-Episode 52 ("Trip to Tomorrow") is almost all animation used from episodes 13A ("Return of the Flying Dutchman"), 29 ("The Evil Sorcerer"), and 36 ("Thunder Rumble") being used in reminiscing past events.
In episode 36 ("Thunder Rumble"), Bolton's voice changes twice in the episode. He starts off with the same voice as the Green Goblin from episodes 6B ("The Witching Hour") 17B ("Magic Malice") and 19A ("To Catch a Spider"), but when he lands on Earth, his voice changes to Parafino's voice, who appeared in episodes 7B ("The Peril of Parafino") and 11A ("The Night of the Villains"). At the point where Bolton says, "You pesky gnat." his voice goes back to Green Goblin's voice.
You must have thought a lot of effort went into composing the music just for the show, right? Not a bit, all of the background music and sound effects was just stock music that came from standard music libraries. Only the theme song was specially composed for the show.
In season three, title screens stayed up a bit longer than the title screens of seasons one and two. In the first two seasons, title screens stayed up for about five seconds. In season three, title screen stayed as long as nine seconds. This may have been to give more time to read longer titles or a subtle way of killing off a few seconds since the production budget was limited anyway.
In season three, and extra screen is added to the end of the credits saying "Based upon the original character created by Stan Lee" with Stan Lee all in capitals.
Episode 1A ("The Power of Dr. Octopus") is home to quite a few one-time-only events. Here's a list of events that happen right in the first episode that never did happen again.
-Spider-Man doesn't do any web-swinging.
-Betty is seen driving.
-Vibrating lines can be seen around Spidey's head when his Spider Sense is tingling.
-Betty shows her Daily Bugle press pass.
-Jameson's talks to someone other than Betty over his intercom.
In seasons two and three, a small animation sequence change was made during the opening theme animation. The scene where the car drives into the giant web was shortened, and a shot of Spider-Man swinging and shooting his web was spliced in; however, episode 37 ("Spiderman Meets Skyboy") uses the season one animation sequence during the theme song.
The only classic Spidey villains used in seasons two and three were Kingpin and Mysterio. Vulture and Rhino could be included in that list, but their appearances don't really count since they appeared in "cheater episodes."
The only crew members who stayed on the show after the first season was the audio and voice cast.
In the first two seasons, the text credits screens cut from one list to another. In season three, the text fades from one list to another.
In the opening animation, Spidey is shown looking at a building with "FINE JEWLERY" listed on it. In the next scene where Spidey is shown swinging through the building's door, the words have changed to "FINE JEWELRY."
In episode 31 ("Pardo Presents"), a small, yellow tube where Spider-Man's web comes out can be seen at one point during the episode.
Every episode was proudly proclaimed "IN COLOR" before the opening theme.