The creators/Steam has got to have a lot of balls to show levels that are NOT IN THE GAME!

[Allard]

Yeah. One of the screens is Intestinal Distress, which is not present in this version.
Speaking of which, all the screens are from the superior Sega Genesis version.

[The Spectacular Batman]

Yeah, I'm not sure why that is. Especially since this version of the game is actually the nicest looking version of all(I can't remember the specifics, but there are technical reasons why this is, mostly to do with colour counts and stuff like that).
Don't bother talking to Steam Support about this, though, since they pretty much ignore anything anyone says about the Earthworm Jim series.