Continuity mistake: Walter near the beginning of the film, is going over the ship's systems. He checks the fetuses inside a compartment and sees a dead one. As he removes it, the slot it came from is full of blood. He places it inside a container. Then as he hits the button to close the compartment, the slot has no blood in the next shot, and no implying he cleaned or decontaminated the slot.
Continuity mistake: Daniels' face gets splattered with blood but when she uses the radio to call back the others, her face on the screen shows no blood. In the other shots after it's there again.