Continuity mistake: Where Swazye and Moore are at the pottery wheel, seconds after their hands and arms had been smeared with clay, they're clean.
Revealing mistake: In the library scene when Richie sees Pennywise the clown, all the balloons filled with blood are popping on people who aren't supposed to be able to see them, but one lands on a lady and you can see her jump as the balloon pops.
Continuity mistake: At the jail bus arrival, the new African American inmate (with orange suit, as the other new ones) is getting off the bus handcuffed and wearing sleek black glasses, next shot, the glasses are gone (handcuffs still on). (00:10:18)
Revealing mistake: In the scene where young Norman kills the horny young girl, as he's talking to Mother, she can be seen moving and even blinking her eyes when the camera's at her back, yet at this point in the movie, she's been murdered and placed back in her bed. Clearly the actress missed the memo.Clerk13