Corrected entry: Eben's right hand is supposed to be severed after punching through Marlowe's head and teeth. When he's hugging Stella watching the sun rise, he is fingering his wedding ring necklace with an intact right hand.
Corrected entry: Near the start of the film, Eben and Billy find a pile of burned cell phones, the phones having been stolen by the Stranger to stop the people of Barrow calling for help. Later in the film, both Eben and Stella are seen using their cell phones. Why not use them to call for help?