Continuity: In the scene where the sergeant crushes the bug with her rifle's butt in the incinerator, we can read "The bug stops [...]" on the side of the stock and the butt is flag. In the next shot where she unfolds Dax, the text is gone and the butt has a clear bump at the bottom.

Continuity: After the sergeant has a parasite bug forced into her, she grabs a syringe kit left on the table by the medic. When she flips it open, there are 7 (maybe 8 at most) syringes in the kit (the last one is broken). A few moments later, private Sandee follows a trail of syringes left on the ground to the sergeant. There are at least 7 syringes on the ground, and 3 others in the sergeant's thigh.

Revealing: In the scene where they fix the door, in the last few frames we see while the door is still moving up, the gear stops spinning in the "rail".

Factual error: During the mess hall fight between the Sergeant and Horton, the Sergeant cuts the private's head with a cleaver and raises it "to show us". Horton's head is heard breathing and the breathing sounds react to the bug coming out of the head's mouth. I know the parasite bug makes the host's body quite resilient, but wouldn't the head still needs lungs to produce breathing sounds of that kind?

Continuity: In the scene where they fix the door, while the door is moving up, we see three cables going over the door's track and strapped somewhat together. On the next shot, while the door is moving down, there are only 2 cables visible and they are positioned in a different way. It is also worth noting that earlier in the movie, when they try to close the door for the first time, the three cables are positioned in a totally different way.

Continuity: In the scene where the sergeant gets the order to get the power up, the person who gives the orders first points at her with two fingers. When it cuts, he only points with one finger.

Continuity: Right after the first encounter with Dax (who is locked in the incinerator), when the soldier comes to warn them of a new bug attack, the chin strap that is hanging from the Sergeant's helmet switches sides.

Continuity: When the troopers repair the tesla fence you can see that when the bug is caught between them they are very close together, yet in a later overhead shot of the outpost the posts are seen to be very spread out.