Continuity mistake: In the early scene in the officers' club, the money in the center of the poker table disappears and reappears with the change of angle.
Continuity mistake: In the inside shots of the airplane, gear is piled up in front of the windows. In the outside shots, you can see clear through the cabin to the windows on the other side of the plane, with no gear or passengers anywhere to be seen.
Continuity mistake: The first time they confronted the thing at the greenhouse door it opened outwards, which is why they brace the door from opening. But later in the movie right before the end, that same door opens inwards.