Spooky game. I like the implicit direction in level design with the light source and also the puzzle aspect. It took me a while to realise the orange panel in the starting area is a door you could unlock with the key and the broken lamp doesn't do anything.
Some technical suggestions:
- It would be to add a mouse sensitivity option, since I use a high DPI setting mouse and the sensitivity is way too high in game.
- Highlight objects in the dark that have been picked up by the player, I threw away some items that ended up in the darkness a bunch of times and couldn't find them again
- Environmental hints (coud be more notes, objects, or writing on the walls)
- Expand the light/dark system to continuous (1-100) rather than discreet (on/off), this could give you more to work with when implementing new systems
Good job!