The first half of "Leviathan" is competently made and surprisingly absorbing, with strongly drawn characters and good acting all around. In the second half, the film degenerates into an "Alien" rip-off (and later on, it even steals a classic scene from "Jaws"), with derivative special effects and too many familiar elements. But it is saved (and gets 6/10) by Cosmatos' professionalism; he certainly redeems himself here for making the absolutely terrible "Cobra" three years earlier.
