Goofs

(at around 1h 14 mins) Lieutenant Joan jumps on the alien and shoots him several times in the head. In the next shot she's shown shooting him in the neck.

(at around 1 min) Star of the film, Amy Manson, is credited as Amy Mason in the opening titles but her name is spelled correctly in the end credits.

(at around 41 mins) Sergeant Logan's rifle makes a Gatling gun noise when firing rounds even though it does not have the spinning barrels that would belong to such a firearm.

The characters are on a spaceship heading to Mars, and even though the direction would take them away from the sun, in an overhead shot we can see the ship moving towards it.

The gravity on Phobos is approximately 1700 times less than that on Earth. Therefore a person weighing 200 pounds on Earth would weigh about 2 ounces on Phobos. Yet the characters walk around on Phobos as if Earth-strength gravity exists on Phobos. In reality a single step would send them slowly careening around the walls. Since the station lost power, there cannot have been a gravity generator as a plot device.

The ivy walls in the botanical chambers are identical to each other, and it's plainly clear that they just kept moving them around as the marines explore and walk around the area.

The rifles and firearms used by the marines are not only obviously made of plastic, but are clearly very light and easy to carry, in comparison to the weight of their real life counterparts.

The floor to the fusion reactor room is clearly the same floor that was previously used in the botanical chamber.

The zombies that attack the Marines are obviously played by the same 5 or 6 actors, who are just constantly reused over and over again as the zombies look exactly like each other.

(at around 16 mins) Captain Hector mentions that it's impossible to dream while you're in hyper sleep, even though it's heavily implied that Joan was dreaming in her introduction scene where she's waking up.

A few characters in the film, including scientists, incorrectly refer to fusion reactors and nuclear power interchangeably even though they're not the same thing.

(at around 41 mins) During the first firefight, two marines run out of rounds for their automatic weapons, clearly showing they are untrained (or poorly trained actors). Real Marines (and in fact pretty much ALL NATO military forces), especially Spec ops would be taught to count their rounds to avoid the so-called "Deadman's Click."

(at around 38 mins) Private Steven is visibly shocked for some reason when Joan tells him that the zombies were formerly human. This should have been obvious to him from the very beginning since they're wearing human clothing and have name tags belonging to the missing scientists.