Before I watched this movie, I didn't realize there were horror movies other than "bloodbath" and "seriously triggering my paranoia". To be fair, this IS a bloodbath, but there is also a running thread of grief, of deep, enveloping despair, and of the naivete of humanity. I cried for the entire second half. The main characters captivated me, the complex emotional and psychological elements swept me straight out of the real world, and I knew what the ending would be, but there were so many moments where I felt such hope that a solution had been found--and then the crushing pragmatism reminded me that, no. There is no other way.
If you want to cry over love and inevitable grief and sacrifice and a creature whose quicksilver changes between violence and restraint are utterly heartbreaking, then please watch this movie.