Continuity mistake: When Billy and Chris are placing the pigs blood above the stage, Billy spills three drops of blood onto Chris' torch, but in the next shot there is only one drop on it. (00:46:00)
Revealing mistake: When Mrs. Schmauss is on her bike, holding a wheelie and spinning after being almost hit by the car, while the other bikers are passing by, a support holding the bike up is visible. (01:29:01)