Continuity mistake: Bobby's hair changes a few times/ways when he is showing Derek the video he made. Lengthwise, his hair on the back of his head doesn't always reach the collar of his shirt. Front shots show Bobby's hair is curled upward and dishevelled. Rear views show neatly (or neater) combed hair that is curled under. The back view also doesn't look like Nick Stahl's thin head or hair; the head is more rounded and the hair is thicker (and neater), suggesting back views are of a stand-in. (00:20:21 - 00:20:42)
Visible crew/equipment: When cousin Derrick and Lisa's mom are sitting on the couch talking, you can see the boom mike reflection swaying back and forth in the window behind the two people.
Audio problem: When the kids are watching the Dr. Dre and Eminem music video on TV, you can hear the song disappearing and reappearing in the background. Some parts of the song are heard multiple times. Plus when you hear the music off screen the "bad words" aren't edited out, like they are in the shots with the TV screen.
Continuity mistake: When Marty and his girlfriend are laying in bed together after engaging in physical relations, Marty lights a joint. It starts off small, but when his girlfriend smokes it then passes it back to him, the joint is longer.
Continuity mistake: The ash in Lisa's hair disappears.
Plot hole: When Marty, Ali and the hitman go back to the crime scene, they go over to the water where they threw Bobby's body. Marty throws up, leaving his DNA at the crime scene. And since he was Bobby's best friend, he's the number one suspect.
Suggested correction: Vomit doesn't contain DNA, unless said vomit contains blood.
Untrue. "While not all these bodily substances provide ideal DNA samples, testable DNA can often be extracted from all of them. In every case, what is being tested is the DNA contained in cells of human tissue, whether found on their own or carried by another substance, like earwax, sweat or mucus. Shed cells are also found in urine and feces, vomit, and even tears." https://www.nytimes.com/2010/11/02/science/02qna.html. Also https://www.mirror.co.uk/news/uk-news/violent-thug-caught-dna-vomit-4017184 "A violent thug who glassed a man in the face has been jailed after being traced down by DNA in his vomit."