Other mistake: When Woods gets shot by the nails fired by the small robot, the amount of blood in his sweater keeps changing during the following scenes.
Continuity mistake: In the scene in the machine shop, when Cpt. Everton sees for the first time the headless body, the tattoo star in the robot's chest is in the left side. Afterwards, it changes to the right side.
Revealing mistake: Near the end when you can see the full view of the ship exploding you can see the waves roll on a beach near the bottom of the screen, they are supposed to be on open sea.