The atmosphere is amazing! It's really creepy and I love it. I got stuck here on my playthrough: 

This was great! You mention that you were focussed on atmosphere and visuals, and it's paid off, it looks really impressive. As has been mentioned in other comments it's refreshing to see a game where dice are used in a non-random way, and it led to some fun puzzles, particularly in combination with the directional floor tiles. 

This game is really well done! It was a very clever way to use dice in a non-random manner. It also created a good atmosphere for dread! One thing I would note is that I got lost  at first for a pretty long time because I missed the second switch. It might not hurt to make it a little more visible, or putting a hint nearby. It could even be something screen dependent, so maybe some kind of brightness slider could be a helpful addition (or maybe something that adjusts the opacity of the walls). Still, I enjoyed the game overall once I got past that, great job!

You can really feel dreadful by the visuals and sounds. The gameplay is also great! Good job!