In the comic book that is part of the game's manual, Roger Wilco is shown as having blond hair, however in the game he has brown hair.
Sludge Vohual is of course a spoof of Darth Vader from Star Wars, and the monkey guards are a spoof of Planet of the Apes.
When you select About SQ2 from the Sierra menu after you die, you'll get a message that says
We hope you're not looking for someone to blame just because you diedrather than the usual message.
Budget re-releases of the game had a copy of the in-box comic in black and white instead of the colour original (well, it was a *budget* re-release!)
The back of the (original release) box said that Vohaul is "...madder than a drenched Astrochicken". An intriguing phrase to use, as Astro Chicken hadn’t yet been seen in either of the games - it would make it's debut appearance in 'Space Quest III'.
For some unexplained reason, Sludge Vohaul's name has mysteriously changed from Slash Vohaul in the first game. (It's not really known why - maybe Sierra thought "Slash" could be taken to sound a little rude for a family game?) Either way, it would remain as Sludge Vohaul for the rest of the series.
In the decontamination area (this is where you change your clothes at the start of the game) open your locker. In your locker there are two objects you can take but there's also this joke. Type:
The game will respond with:
Sorry. The used Nancy Reagan autographed "Just Say No" condom had to be removed for the shipping version.
A big thank you to the excellentVirtual Broomcloset website for this one.
When you're inside Vohaul's asteroid, go to the bathroom on the 4th floor and enter the booth that isn't occupied. Close the door and type:
Among the responses (just repeat the command a couple of times to read them all) the game gives you there's this one referring to the hero from King's Quest:
"Sir Graham Cross Dresses!"
Another one is:
"Ken was here! (So was Al, but we had to repaint afterward.)"
Ken & Al are of course Sierra developers Ken Williams & Al Lowe.
One little quirk: Space Quest 2 is the only Space Quest where you do not use Buckazoids (the Space Quest intergalactic currency).