Leaves the fear to your imagination(this review contains spoilers)
So many good ideas in this movie! Apparently aliens have come to earth and they cause visions that strike so much fear into the people who see them that they immediately kill themselves. Except for the insane, who find the visions enjoyable!
In the best horror fashion, we never get to see exactly what it is that scares people to the point of suicide. The protagonists blindfold themselves to avoid seeing the alien visions, and the director takes full advantage of this fact - frequently showing us a dark screen of the view through the blindfolds, instead of the aliens. I was wondering why this is such an effective horror technique. I think it's because each viewer has their own unique fears, so if the movie were to be more specific then some viewers would find it very scary but others not so much. But by showing the physical symptoms of the the fear on characters who we have come to empathise with, the movie can conjure the scariest of each of our thoughts.
At one point we do see some pencil drawings by one of the insane people who enjoys the alien visions. They are all different. One was some kind of tentacle monster coming out of a wormhole, one looked like a skeleton, and one looked a bit like Cthulhu. We only see these for a moment, and the fact that there were many different indistinct drawings still leaves the viewer to focus on what they find most scary.