Goofs

After they shoot the first alien and walk outside to see where he went, you can see the windows of the cabin boarded up behind them, but it's much later in the film when they actually put the boards on the cabin's windows.

At the very beginning, the store clerk says the woman was banging on the door, asking to use the phone. She never asked to use the phone, she only asked to be let inside.

When filming on his camera, Seth mentions that there is no TV in the cabin, but Later (at around 1h 7 mins) there is a close up shot of the television exploding during the attack.

in the final scene,the man in the suit lights up and lowers his cigarette in his right hand, but the cigarette is in his left hand when it comes back up.

When April first loads the shotgun, the primer pocket of the cartridge is empty, meaning it won't fire, yet it does a few minutes later.

April loads the shotgun, then snaps the barrels into place on the stock. There is then the sound of a round being chambered into a firearm. That couldn't happen with a double barreled shotgun. Once April snapped the barrels into place, the shotgun was ready to be fired.

While the girls are talking to Travis, one of them puts on a helmet, presumably from his military service. The helmet shown is shaped like a modern Kevlar helmet, where the brim dips near the ears. If Travis was in Vietnam, his helmet would have been the old "steel pot" , with a straighter brim.

Although a fallen tree is shown being down and blocking the road, it's clear from a wide shot that the SUV that the characters were in could easily have driven around the stump and back onto the road beyond the blockage.

When the group of friends flee the cabin they are blocked by a tree across the only road to town. But the police later arrive to the cabin by car.

When the sheriff shoots the deputy inside of the squad car it's clear that the door on his side is not in place as he has more than enough room to maneuver the weapon to shoot him in the mid-section. Additionally, despite seeing the sheriff about to point a shotgun at him the deputy does nothing to block it or grab the sheriff's hands.

When Seth lights the glow stick in the forest near the end of the movie, Seth's face lights up green, supposedly from the glow stick. However, the prop lighting is angled poorly so the glow stick casts a shadow on Seth's face (which obviously wouldn't happen if it were the source of light).

When April is talking to her dad via video chat, they discuss taking photos for the realtor because the realtor charges too much. Realtors do not charge for taking photos of a property to list, they charge a percentage of the sale only.