I had never actually played through this until today, and I'm very glad I finally did. The atmosphere in this level is extremely convincing, and it gave me a constant feeling of uncertainty from beginning to end. I do think some gameplay spots could've been telegraphed better, and the hitboxes towards the end are a little confusing, but this is truly some of the best song representation I've seen in GD

Few levels utilize emptiness in a way this level does. The constant repetition of similar structures over and over and over adds so much to the absolutely dreadful atmosphere the level creates, and this is without a doubt my favorite non-demon level ever made. However, this wouldn't be as good as it is without the song it uses; Red Observer is a terrifying minimalist ambient track that fits the atmosphere of this level perfectly. The gameplay itself is slow enough for you to take everything in, and makes this level feel 10x longer in the best way possible. A truly outstanding example of minimalism in this game, and my personal pick for the most underrated level ever made.