At 38mins in the flame thrower guy's head lamp keeps changing position.
When Grant is killed, Kate is firing an AK47 at the alien but the large safety lever on the right side of the gun is clearly up in the safe position. It is impossible to fire a real AK47 with the safety on.
Early on in the movie you here the helicopters as they come into view from behind a building. In reality one would have heard them before they cleared the building and became visible.
When Alexi detonates the explosive device over her chest and takes out several aliens, her body escalates from the explosion, yet this would not occur because of gravity and the fact the explosive device was above - rather than below her.
In the middle of a cave on a distant planet one of the characters shouts "movements on the east wall".
How do they know what's east or west. Those terms can only be used on earth.
Dude kicks a guy into a doorway, then knocks him through it, closes the door and uses a keypad to lock the door. Normally, one would close/lock the door, and use the keypad to unlock it.
At 38mins Col Owen is holding his rifle incorrectly, a Navy Seal is so well trained that proper positioning of his rifle would be 2nd nature to him.
Col Owen's ribbon rack has too many ribbons on the top row.