During the party scene at Hardy's house, after Keith wrestles with Hardy, Keith's hair color and style change after they're separated.
When Keith's sister Laura is talking to her friends about her new "popular" status, she has a military-style vest on over a yellow blouse. When she jumps down after being accused of being "false", the vest is gone, but immediately reappears in the next shot.
When Keith's dad is talking to him after Keith gets out of the shower, his hair is wet; in the next scene the front has dried and it's all wet again in the next scene.
After Keith checks the oil in Hardy's car, he closes the hood, walks around the car, takes the gas out and puts it back, stands by the side of the car. and picks up the money Hardy drops. During this entire sequence, it's obvious that he hasn't the dipstick in his hands, but after Hardy drives off, it appears in his hands and he throws it away.
When Keith gets home from taking his savings out to the bank and starts to go upstairs, he puts his sunglasses in his shirt pocket, but when his father calls him into the room, they're hanging from the front of his T-shirt.
At time index: 0:34:29 you can see the dog tags being worn. The secondary dog tag chain is far too long. The typical length is 4" whereas this one is 6 plus inches long. There are no notches showing so these dog tags are likely from later part of Vietnam Era and newer from multiple services although more likely U.S. Army.
When Watts and Keith are sitting together at the nightclub, the music doesn't match the band's on-stage actions.
Shayne's Suzuki has a California license plate, though the movie takes place in Illinois.
When Keith borrows Watts' car to take Amanda home, the engine won't turn over and he then grabs a ride home with Amanda in Shayne's car. Yet, Keith works in a gas station and garage so you would think he would know how to fix Watts' car.
Watts deliberately covers a star tattoo above her collar bone with make-up while getting ready to chauffeur Keith and Amanda, but when she's in the chauffeur outfit, the collar is high enough to hide the tattoo on its own.