These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Continuity Lock-Out: Whenever they run into Walter, Jim refers to him as his old prison buddy and Walter calls Jim "Floss" with no further explanation, which may confuse viewers who didn't see the episode "Conquer Worm".
Ear Worm: Basically every musical piece in the game, which ranged from creepy Danny Elfman-like weirdness, to classical music, to funk/electronica/pop.
Moment of Awesome: For the TV series, the end of "The Egg Beater." After Jim fought them in separate battles throughout the episode, his usual enemies get together to eliminate him. That's seven (eight if you count the monkey) enemies, as well as a stressed-out, transformed Peter Puppy to worry about. In the ensuing battle royale, Jim either outsmarts or outright Curb Stomps them all before a more prolonged battle with the Queen that sees her beaten. And he keeps count of his victories in the process!
Nausea Fuel: From "Snot A Problem" to "Intestinal Distress," the series is notorious for grossing people out, primarily on purpose.
The music for the Intestinal Distress and Big Bruty stages are creepy. Especially compared to the rest of the music in the game. And Queen-Slug-For-A-Butt's graphic explosion after you defeat her in the first game.
The background during the boss battle with Evil the Cat features a legion of creepy, malicious stone faces. In some versions of the game, however, there's just a regular pitch black background.
Porting Disaster: The first game was on many systems, but with the exception of the Sega CD and PC version, it got worse with each one! It lost a level on the SNES version, and you should expect what happened when they tried to port a game that pushed the Sega Genesis and Super Nintendo to the very limit onto the Game Gear and Game Boy. The GBA port of the first game wasn't all that bad as far as recreating the game, but it lacked a save feature, rendering it near-useless as a portable game. But Earthworm Jim 2 on the other hand was a disaster.
The recent "HD" remake for PS3/360 was pretty good; only one problem: They omitted the secret level "Who Turned Out the Lights?" for some unknown reason. So the problem continues to this day.
The SNES version also took a lot longer to actually start the levels, almost like it was loading them. The underwater stage was also missing its music, using New Junk City's theme instead.
The PC port tends to be remembered fondly, but not many realize there are two ports of the first game, that are made by two teams: one is a Special Edition port for Windows 95, other is a DOS port that came in the Whole Can O'Worms edition. And while first is pretty good, second is not. While graphics are good and music was taken from Sega CD version, the controls are so-so, collision detection is not that good either and they took out not one, but two levels (Intestinal Distress and Who Turned Out The Lights?). The same team made PC port of Earthworm Jim 2, which has identical features to their port of Earthworm Jim 1, but this time they took out only one level (Lorenzen's Soil). The saddest part is the version now available at GOG.com and Steam is the second one.