Other mistake: Towards the end of the movie, Clayton has two wounds visible on his face. These wounds keep changing length and shape throughout the scene.
Other mistake: When Clayton shoots Zack, both the position of the gun and the location of the blood on Zack's jacket are about mid-torso on the left side. Yet not only is Zack shown to die in only 15 seconds, but Clayton does nothing to check pulse, breathing, pupils, or even the wound, which is inconsistent for this trained agent who didn't want to kill his friend; instead, he retrieves a paper from Zack's pocket and flees. (01:25:46 - 01:26:27)