Revealing mistake: During a few of the "flaming fart" scenes, you can see a wire connected to the bottom of the actors. It's hard to see because it appears that it was attached to their legs in some way, but you can still see it when they move around a lot. The easiest place to see it is when the "devil" knocks on the door and they all fart and jump around, look carefully between/to the side of eddies legs for a black wire. It's not the dressing gown belt because that's tied around their waists.
Character mistake: Eddie, Spudgun and Dave Hedgehog all appear worried at the fact that the devil takes "virgin's blood." However, it is apparent later in the episode that the 'devil' is in fact Dave Hedgehog's daughter, meaning he isn't a virgin.
Suggested correction: Also, Eddie previously slept with the Third Viscountess of Moldavia when Richie's back alley kidney donation backfired and he collapsed, so he wasn't a virgin either, but reacted as though he was.
Although theoretically correct, bear in mind that neither Eddie or Dave Hedgehog aren't particularly bright, and likely forgot they weren't virgins.
Hedgehog's daughter could have been adopted.