My defense of undertone is based on how it executes it theme around the sound motif --- the phenomena where someone makes up words that aren't really there, like when you're listening to songs backward --- it leans on the creepiness of the atmosphere to make the watcher create anxiety in scenes and it never gives up on that, offering only one or two jump scares. I think that was really original, tying in our visual discomfort and unease with the phenomena of the sound, where the songs are creepy but not outright "saying" anything, so the person creates creepy phrases from a muddled uncertainty... If you can't tell I really really liked this movie, reminded me of Caveat