Revealing mistake: The size of the spider walking off Sam's face becomes disproportionately smaller too fast compared to its size while on her cheek plus the spider's awkward movements are indicative of CGI. (00:02:20)
Continuity mistake: The laceration near Ryan's right eye extends into his cheekbone but it is much shorter and looks closer to his eye several minutes later. (00:08:30 - 00:13:55)
Continuity mistake: A full moon was shown, but it was quite dark even around the campfire. When the man came and said there was something in the field, the sky was black. About a minute later when Cameron tripped/fell, there was (moon) light near the ground. (00:16:09 - 00:18:19)
Character mistake: Sam told Tyler, "I work 36-hour shifts, so no time for friends or relationships." There might not be Federal regulations restricting the number of hours a nurse may work in a given 24-hour (or 7-day) period, but nurses have to maintain standards of duty/care and working too many consecutive hours would jeopardize her patients. It is recommended that nurses do not work more than 12.5 hours a day or more than three consecutive DAYS of 12-hour shifts. This gives 4 days OFF for relationships. (00:26:50)