Visible crew/equipment: You can see the strings on Pumpkinhead when they are killing him at the end.
Revealing mistake: When Pumpkinhead picks up the guy to break his back, as he's doing this, you can see its not a real person. Looks like a stuffed doll.
Continuity mistake: It was six red wings who killed Tommy but only 5 people were killed, and on more than one occasion, the sheriff and the doctor kept saying the Judge was the 6th victim. When the sheriff had the year book opened to the picture of the 6 red wings, he called each one's name but only called 5 names despite 6 people in the picture. I've done many searches for mistakes and goofs on this movie and none mentioned this. The 5 killed: the guy in the barn, the one that just had sex, the 2 brothers and judge.