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: In the scene where Freddy turns into a puppet, he cuts his own strings with his knive fingers to get down and as he falls you can see some strings still attached to him, but when the shot changes and he lands on the floor, there are no longer any strings attached to him.
Continuity mistake: The day Kristin is admitted into the hospital, she is screaming and fighting with the staff. She then cuts Max on his right inner arm with a scalpel. In the next scene where Max is introducing the kids to Nancy, Max has a very small band-aid where Kristin cut him yet the band-aid is on the outer part of his arm by his elbow.