Crew or equipment visible: When Sgt Foley has the new recruits lined up and tells them that they will fail, the dolly tracks of the camera are visible. Foley can be seen to carefully step between the rails.
Continuity: Zack's grip on Foley's arm during the fight scene.
Continuity: Zach enters Sid's motel room to see him hanging, naked, in the toilet. Zach runs to cut him loose and grabs him round the waist, and the camera angle reveals the underpants Sid is now wearing.
Continuity: Just before the fight seen between Mayo and Foley, Mayo has red marks on his back probably from previous takes. Then later on in the fight scene the red marks disappear.
Continuity: Just before the officer candidates take the oath and graduate a recruit announces, "All officers present." The candidates' swords are up on their shoulders but in the next shot the swords are in their scabbards.
Revealing mistakes: During the factory cafeteria scene where Paula is trying to reach Zack on the phone, a co-worker mentions to Lynette that it's 3:40 PM on a Friday and she's not bragging about their weekend plans. A moment later when Paula runs from the cafeteria to find Zack, the clock on the cafeteria wall reads 12:50PM. Also, many employee's appear to be eating lunch.
Errors made by characters (possibly deliberate errors by the filmmakers): During the graduation ceremony, when Gunnery Sergeant Foley reports to the officer and falls out the graduates, he does an about face and steps off with his right foot. This is incorrect, as you always start with the left foot when marching.
Continuity: When Gunny Seargent Foley has Zack Mayo doing push ups in the sand pit, it's noticeable that his forearm sleeves are already wet from getting into a prone position to chew the recruit out, before he actually does it.
Factual errors: During the graduation ceremony the students are wearing the Service Dress White uniform and the reviewing officers are wearing Service Dress Blues. In reality they would be wearing all the same uniform one way or the other but never different as uniform season requirements are dictated by a senior officer (usually an admiral in control of the Naval region).
Errors made by characters (possibly deliberate errors by the filmmakers): The class, upon receiving their commissions, approach Gunnery Sergeant Foley and present him with a silver dollar, in return for their first salute. When Ensign Seeger receives her salute, Sergeant Foley says "Congratulations Ensign Seeger, Sir". He should have said, "Congratulations Ensign Seeger, Ma'am."
Factual errors: For the entire movie, Gunnery Sergeant Foley is called either "Sir" or "Sergeant". While DIs at OCS are called "Sir" (despite being enlisted), a Gunnery Sergeant is never called just "Sergeant."
Revealing mistakes: Right after Sid's body is loaded into the coroner's vehicle, we hear the sound (offscreen) of a siren on a departing vehicle. A coroner's vehicle would not even have a siren, much less that it would be used on the trip from the scene back to the coroner's office.
Errors made by characters (possibly deliberate errors by the filmmakers): Mayo wouldn't have been allowed to ride his motorcycle on a military base without wearing a helmet.