Patzer

In the beginning of the scene where the group is sleeping in the desert, Reggie goes to get Mike while Rock lies next to him and Tim lies on the other side of the campfire. But when Reggie comes out with Mike, Tim and Rocky are next to each other.

(at around 1h 26 mins) At the end of the movie when Tim walks through the double doors there is a toilet in the background which wasn't there in the previous scene, there was a table in its place earlier.

Early in the film, after the car crash, Reggie shoots his three-barreled shotgun at the minions in the branches. Although he shoots straight up, the three bodies that fall from either side of him, and no one falls from straight above him.

During the night scene at the young boys house, the boy without explanation leaves his window curtain open. This is not only very stupid, but the scene before this, the boy even explains that Sentinels come out at night. So why did the boy leave his window open, knowing that the sentinels come out to spy at night??? Clearly done so the film crew could get the Camara shot they needed and makes little sense within the film.

(at around 2 mins) In the white room, the camera pans from the Tall Man's corpse to the fork gate to reveal a new Tall Man emerging. Briefly, you can see the actor's reflection in the rightmost prong as he waits for the right moment to pop out.

A wire attached the sphere is visible in certain shots.

When the spheres fly in the air, you can see the reflection of a "dot" following it - the camera, which is covered by another mirror, which also reflects the crane carrying the sphere.

Reflected in the sphere.

When the boy encounters the two thugs outside, one of them clearly has a gun, but they refuse to shoot him, despite the fact that he is standing well within the range of the gun and the spend there time talking. This is not only a serious mistake, it's gets them killed the first time, when they could have simply shot the kid, and been done with it. This makes no sense.