Continuity mistake: When Richie falls off the ladder, it's apparent from the way he falls that he lands on his front (you just see his leg pop into shot) and that his head would be pointing towards the camera. However, instantly in the next shot we see him on his back with his head towards the wall.
Apocalypse - S1-E4
Revealing mistake: When Eddie falls through the ceiling playing the piano, it's very obvious from the back that it's a dummy because it wobbles around but is stuck to the seat.
Revealing mistake: When Richie says "Don't you dare call me overweight young man" and tips the ferris wheel cart over, you can see that it is a dummy representing Richie.
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.
Continuity mistake: When Ritchie yells "Aah. Aah. Aah." after the table lands on his toes, the shot zooms out. When Eddie hits him again, he is able to move away from the table. But we never see the table moving the final distance downwards towards the floor (implying he's pulled his feet out from under it), meaning his toes were never under the table at that point, only in the short scene beforehand.
Bottom's Up - S1-E5
Continuity mistake: When they are first on the roof, Richie is seen looking through a telescope on a stand. However, it is gone a few moments later, and doesn't appear at all for the rest of the episode.
Bottom's Up - S1-E5
Continuity mistake: When Eddie goes down to fight the looters the sky is totally blue. But all of 2 minutes later when he comes back on the roof, the sky is totally grey. Not a chance could that happen so quickly.
Continuity mistake: After Eddie has performed checkmate on Richie, Richie punches Eddie who falls over. Eddie gets back up and lifts the table up. The chess board, ashtray, bottle of brown sauce and other things on the table disappear completely in the next shot showing the table land on Richie's feet.
Revealing mistake: When they are leading Richie to the cupboard while playing postman's knock, Dave Hedgehog puts his hands on the wall. The whole stage wall shakes when he touches it.
