For a game made in so little time, it's quite impressive, especially considering that it is complete. I liked that shader and the geometry work.
At the point where there is the "There is no hope" writing on the wall, though, I accidentally clipped out of the cube, and I was free to roam in the forest and the mountains. I was not sure if that part was intentional or not, so I was looking out for a possible monster to come out of the fog to eat me! It was pretty fun, even if that was a bug, but it's definitely a concept to explore!