Revealing mistake: The helicopter scene shows a brown skin-toned hand holding onto Schmidt's hand, a couple of times, and then it shows Jenko's white hand again.
Other mistake: In the first scenes of the film, we see the truck in which Jenco and Schmidt are going and moving away from Ghost, but while the truck is running we see Ghost inside it, sitting in front of the driver.
Factual error: Near the end of the helicopter scene Jenko pulls the pin of a grenade with his teeth before he throws it. It is not possible to pull a grenade pin with your teeth as it requires more force than that.
