Deliberate "mistake": In the shot near the end of the film where Donnie grabs the keys for the station wagon, you can see a Blockbuster Video member card in a cup. That card design wasn't used until the mid to late 1990's. This movie is set in 1988. Deliberate as it's a product placement, but still wrong.

Visible crew/equipment: When Donnie and his Dad are in the car, talking, prior to nearly hitting Grandma Death, in the window behind Donnie's Dad is the reflection of a vehicle which says "Darko" clearly on it.

Continuity: When Cherita makes her mark on the lifeline blackboard, there are some smudges on the broad chalk line. In the next shot, the line is perfect again.