It was a fun game!
I love how the game guides the player to understanding the game mechanics without using a tutorial, and it fits my personal taste that it's possible to get hopelessly stuck in some puzzles so you have to reset manually. Apart from that the lighting really was perfect, the music fit perfectly, and it absolutely deserved to be tagged atmospheric!
It's a bit of a small mistake, but moving diagonally shouldn't be faster than moving in a straight line. It makes straight line movement feel slow and tedious. The viking should also have the same round collider as the bat, to reduce the risk of getting stuck at a corner. Apart from that you should be careful about accidentally confusing the player. In the puzzle where you had to give the candles the right colors, there was an "press e to interact" arrow over the glowing pillars, but pressing e did nothing. Glowing pillars really don't need any arrows to draw the players attention, but if you want to draw the players attention to something in the future, consider doing so in more subtle ways. Drawing faint red lines on the floor, placing things so that the player can't avoid walking past them, or just making them stand out of the environment using unusual colours and designes.
Overall I think that you did a good job for a 5 day game, but if you had more time I hope you would have ironed these things out!