Harken's car crashes hard into the driver side of Kurt's car at the end, causing the air-bags to deploy. The speed and impact of the crash doesn't seem to have any effect on that side of the car moments later when Dale and Kurt get out showing no smashed windows or even a dent on the doors.
When Nick, Dale, and Kurt are talking to "MF" Jones in the bar, "MF" Jones moves the briefcase to the side of the table. However, it is back in front of him in several closeups and at the end of the scene when he tells them to leave.
When Stacy covers Dale's eyes and he turns over to confront her (thinking her to be Julia) he turns from the right side, but in the next shot we see his body facing from the opposite direction, as if he had turned from the left side. The switch continues between shots.
When Harken checks the contact information on Pellitt's phone, it lists Pellitt's address as "Riverside, CA 92595." ZIP code 92595 is assigned to the city of Wildomar, California. Wildomar, while located in Riverside County, is about 40 miles south of the city of Riverside.
After Dale's fiancee, Stacy, becomes unconscious via nitrous oxide inhalation, Dr. Harris tells Dale to prepare the patient for a bite-wing x-ray. This type of x-ray requires patient cooperation, and would have to be done before she was sedated.
The goof item below may give away important plot points.
Forensics would certainly find out by checking gunpowder particles in palms that no one from our three heroes didn't shoot from gun (but would find them in Dave Harken's palm). Bullet trajectory through Dave's leg would also revealed that shot was fired from directly above leg at almost point blank range.