Mr. Anderson claims that it was Charles Dickens who left a character literally hanging by his fingers in a serialized story, thus contributing to the term "cliffhanger." In fact, the author was Thomas Hardy, in his 1873 serial novel A Pair of Blue Eyes.
After Patrick is tripped by one of Brad's friends in the cafeteria, the bottom of his shirt is tucked under his arm. After he says, "Your pet ape just tripped me," his shirt was back to normal. In the next shot, it's tucked under his arm again.
During a closeup of Sam and Patrick doing the "Living Room Routine" at the dance, Charlie's face can briefly be seen entering the left side of the frame, before he'd even stepped onto the dance floor. The shot immediately cuts to Charlie up against the brick wall and he steps forward to join Sam and Patrick.
During the end of the first semester, Patrick tells his shop teacher that if he fails, he has to retake the class again next semester, so his teacher gives him a C-. Though Patrick passed, he is seen taking the class in his final days of second semester.
Sam is regarded as a music fanatic, particularly in regards to artists belonging to the glam and new wave genres. Anyone with any significant exposure to this music would undoubtedly recognize a David Bowie song by his voice alone. It is not believable that it would have taken Sam more than a school year to identify the tunnel song as David Bowie's "Heroes."