When Ken Walsh is on the ladder removing the bars from the window during his argument with Cheryl, in the shots of him, Ken is wearing a solid blue shirt; in the shots of Cheryl, he's wearing a plaid shirt.
(at around 35 mins) When the coach is getting bombarded by basketballs and volleyballs one of the balls flies out, smacks him in the head and then bounces on the floor. At one point it is a volleyball and at another point it is a basketball.
(at around 2 mins) In the opening scene, the kids on the bus are seen standing up and walking towards the door while the bus is still moving. In the next shot, they are all sitting down until the bus stops.
(at around 7 mins) When Jesse's sister shows him the "Fu Man Fingers" they jump from her left hand to her right between shots. Also the cereal box she pulled the Fu Man Fingers out of, the box was on the table before she pulled them out. In the next shot the box is in her hand, then she pulls the Fu Man Fingers out.
(at around 10 mins) When Jesse and Grady are fighting with each other on the school baseball field and coach Schnider starts to walk over, in the background you can see a male crew member behind the coach. In the next shot you can see him encouraging Jesse and Grady to keep fighting with each other.
The fictional location for the Nightmare on Elm Street franchises was Springwood, Ohio. Throughout the film Palm Trees are visible in the background which cannot be grown in Ohio climate and the bus in the opening scene drives through the desert, which is not part of Ohio's geography.
(at around 1h 7 mins) When Freddy Krueger jumps through a glass door and disappears mid jump. At the point he vanishes, so do several pieces of the doors debris. Clearly there were two takes, one with Freddy jumping, one without and they simply faded between them. This is very noticeable if you look at the door pieces at the top left of frame.
There is an instance in which the same scene is used twice: after the gym fight when Grady and Jesse are holding the push-ups pose in the field, as punishment (at around 10 mins). This is the same scene used for when Jesse insults Schneider in the locker room (at around 28 minutes). The same people pass behind the fence.
(at around 1h 10 mins) During the pool party, one teenager attempts to reason with Freddy, only to be slashed by Freddy and thrown towards a fire. When he is thrown towards the fire, there is no injury or damage to his clothes where Freddy slashed him.
(at around 1h 8 mins) When Freddy attacks the kids at Lisa's pool party, he kills the first kid by slashing him diagonally across the right side of his face and neck. When the kid drops to the floor, the wounds are vertical and on the left side of his face.