Revealing mistake: Each crew member has a monitor on their spacesuits that they use whenever they are exploring the caves. Whenever the monitor is shown, each crew member's individual heartbeat is shown in the lower left corner of the monitor. But no matter which heartbeat is shown, every time a heartbeat on the monitors is shown, it is always the exact same heartbeat, despite the various changes in panic and stress throughout the movie.
Revealing mistake: When Fifeld and Millburn find the dead bodies, just after Millburn says "This thing opened up from the inside. Looks like it exploded", the shot cuts to Fifeld flashing his torch over the corpses. During this shot, a corpse's arm to the right of Fifeld is shown wobbling around.
Revealing mistake: When Shaw goes to the med pod for her emergency surgery, as she quickly taps on the entrance door to the med-pod room, on the left-hand side of the frame you can see the door is already partially open and then opens before Shaw has finished typing in the code.
Answer: The giant ship has landed on Earth to drop off the Engineer so that he can terraform the planet and make it sustainable for life. He might drinks the black stuff to break down his own structure and spread life on Earth through his own DNA.
Anastasios Anastasatos