You should tell the player the "E" key is to open the door. I have spent 2 minutes trying to open it haha
The game looks stunning, honestly. We also made one with Unreal Engine but it does not look as good as yours, so hats off! I like the idea although some of the puzzles were not very clear to me, like when you have "A, B and C" as options and the "Numbers of all doors". The rest are very clever and I loved the fun part before the end. Cool animation in the ending as well. Congrats!