(at around 34 mins) During Carlos's nightmare sequence, Freddy cuts off Carlos's right ear. The ear reappears and disappears in subsequent shots. Furthermore, when Carlos gets his ear back, he puts it on his left side.
When Spencer, Tracy, and Carlos enter the empty house in Springfield, the lights in the front door window are on. But when the door is open, you can see that it is pitch black inside. When the door is shut again, the lights are on again.
(at around 47 mins) When Spencer is almost falling off the edge of the top stair (and the ledge in Freddy's video game), in his shadow you can clearly see the cord attached to his harness keeping him up.
(at around 1h 7 mins) When Freddy is talking to Doc and cutting off his fingers, a white tube held between middle and ring fingers spurting green liquid is visible (both from Freddy's perspective and when the shot faces Freddy).
(at around 28 mins) When John Doe and Maggie go to the school, Maggie finds a scrap book filled with articles related to Fred Krueger. In a close up of the book, an article is titled "Krueger Sought: Boy, 7, Missing" but the text that follows discusses baseball (Yankees, Kansas City, and the Mets) on the left side and military action in Vietnam on the right side.
(at around 1h 5 mins) When Freddy appears to Tracey as her father and he turns his glove into a buzz saw, the wires for the fake Freddy arm are visible. Also you can see Robert Englund's right arm sticking down, in front.