I totally understand if you already voted not useful. I can't always explain what I think or what goes on ... thought process and all that. I just type what comes to mind. Now I'm not suggesting the scriptwriter here had the same inclinations. Especially because this is based on a novel that I have not read yet (so no comparisons I can make to that).
Interesting premise, interesting story to say the least. Gets way cliche towards the end, so a bit of letdown. At least I felt that way. I would have gone higher rating, if it didn't try to just ... do the easy way out. But still for the very powerful beginning and a lot of visual and otherwise treats this serves you, I think one can watch this and be entertained (if you are into horror science fiction stuff).