The last bike of the funeral procession has a flat rear tire.
A nurse is sexually assaulted by a biker that wears wraparound sunglasses. She looks through a book of police mug shots and finds the guy's photos and he's wearing the same wraparound sunglasses in the mugshot. Police would not allow someone to wear sunglasses in jail or in a police mug shot essentially giving him a disguise.
During the final party, Loser's corpse moves his arm towards his chest.
During the funeral procession, one of the bikers glances into the camera.
When Loser has his surgery, the surgeon does not prep the operative site before draping it, nor does the anesthesiologist prep the IV site before inserting the needle.