Revealing mistake: When Freddy pulls open his head, revealing his brain right before he pulls his skin back, you can see his eyelashes in one shot with a close-up of his face.
Revealing mistake: When Freddy bursts out of the ground at the pool party look closely. The facial makeup's different looking. Clearly this a stuntman.
Other mistake: If Freddy ripped his scalp off, it would be his skull, not his bare brain. It's not like he pulled both of them off at once. Freddy's got a skull, as we saw when Tina took his face off in the first film, so why is the top of it missing in this one?
Suggested correction: This scene takes place within Jesse's nightmare, which is Freddy's domain, so Freddy can manipulate any detail he wants, in this case, exposing his brain without cutting open his skull.
Continuity mistake: When the two boys are told to assume the position, the amount of grass on their tops changes between camera angles.
