Visible crew/equipment: When the boy who wanted to be a wizard is being chased in his dream, they are in a dark tight corridor, and Freddy releases a chair with spikes on it to chase after the boy, but if you look you can clearly see the chair is being pulled with strings.
Continuity mistake: When Max turns off the lights, the switches are already down - he doesn't move them in any way (neither up nor down) and therefore hasn't made any actions that would alter the current lighting situation, however the lights turn themselves off anyway even though it is apparent the switches were not moved. Nobody else moved any lightswitches either.
Continuity mistake: When Freddy and Kristen are fighting in the boiler room, there are some barrels full of bones. Later they disappear.
Continuity mistake: When Philip is sleepwalking, he walks out of the room since the door is wide open. Yet in the scene where Joey is slamming on everyone's doors to wake them up, we see that the door to Philip's room is shut because Kincaid is seen opening the door.
Plot hole: The group talks about Phillip's death. The doctor says Phillip's death was a sleepwalking accident, nothing more. Then the other doctor says it was suicide. How do you explain either situation when the door was padlocked with no way out to the very top of the building where Phillip fell?