Common Knowledge: Contrary to popular belief, Tommy Tallarico didn't compose the music for the first Earthworm Jim game; that was done by Mark Miller of Nu Romantic Productions. However, Tallarico did re-arrange tracks and create a few new ones for the Special Edition re-release on Sega CD and composed nearly all the tracks for the second game.
As for individual levels, Big Bruty, from the Sega CD and Windows 95 versions of the original, gets this, even being excluded from the HD remake. If not for the WiiVirtual Console release of the port of the Sega Genesis / Mega Drive version, Who Turned Out the Lights, which also got shafted from the HD remake, would have been this as well. And then there are the speeches, which serve as alternate endings in the Sega CD and Windows 95 versions as well.
Port Overdosed: The original game. Not only was it ported to every contemporary system, including handhelds, but it has been almost continually re-released since then.
What Could Have Been: A PSP game was planned, and apparently almost done, but due to financial difficulties, it was cancelled.
Sega also considered the possibility of putting a port of the Sega Genesis/Mega Drive version of the original on Xbox LIVE Arcade, and made a poll with some other games to see people's opinions on whether it or other games should be on there. They scrapped that possibility when they found out that Gameloft was working on an HD remake for the same service.
Both Doug TenNapel and David Perry initially served as minor consultants for Earthworm Jim 3D, but were dropped for unknown reasons. One can only wonder how it would have turned out had they stayed.
Creator Backlash: This is the sole reason why this series was withheld from DVD release for so long. It did have a brief but memorable stint being released on VHS around the time that VHS was on its last legs and DVDs were becoming the next big home video format). Allegedly, despite it being a very funny and entertaining show, Doug TenNapel hated it and confessed to only doing the show as a tie-in to the video game.
Except that it DID finally get a DVD release. First in Australia, then a more limited US release, though see below with that.
Hey, It's That Voice!: The voice of Earthworm Jim is Dan Castellaneta, best known as the voice of Homer Simpson and various other Simpsons characters (particularly Grampa Simpson, Krusty the Clown, Sideshow Mel, Barney Gumble, Groundskeeper Willie, Mayor "Diamond" Joe Quimby, The Squeaky-Voiced Teen, Arnie Pie, and the Mexican Bumblebee Man). Jim's cowardly shriek is a dead giveaway, being exactly the same as Homer's.
One opening sequence has Jim doing standup comedy about superheroes. His "old superhero" voice is the Old Jewish Guy (the one who used to be a studio executive around the time It's a Wonderful Life was released and who gained minor fame as a TV star singing "The Old Grey Mare" with his pants around his ankles. He even had a band called "The Crazy Old Man Singers.")
Keep Circulating the Tapes: There were actual official release VHS tapes back in the mid-1990s (with select episodes), but with DVD becoming more popular than VHS (and Doug TenNapel refusing to having anything to do with the show, since he only did it as a tie-in to the video games), this petered out real quick.
The American DVD release – which didn't even include the extras from the VHS tapes – was put out by a company known for supply issues.
Screwed by the Network: It suffered the same timeslot demotion as Freakazoid!! It was in a more precarious position though, as WB didn't make it, Universal did (their animation studio was also known for making Exo Squad).
Talking To Herself: In the episode "The Exile of Lucy", Queen Slug-for-a-Butt is deposed and sent to Earth, where she meets and befriends Mrs. Bleveredge, with whom she shares a voice actress.
What Could Have Been: Playmates Toys' tie-in action figure line went out of production before Professor Monkey-For-A-Head (among other characters) got released, much to the dismay of children and nerds everywhere.