Love the atmosphere of the game. The sounds are nice, effects as well, and it creates an otherworld-y mood. I liked the sound for coin pickup. I played twice - on my first try, I brought all keys from areas to the center even when a door was unlocked. I also thought the darkness might spawn ghosts so I kept carrying my torch and dropping/swapping with key every few metres, so it was slow going.
Spoiler about gameplay:
!> The second try was much more fun - I ran in the darkness, progressed faster, and even got to the graveyard. I hand't used any of the health potions yet so I was feeling real confident I could make it. I gathered all the keys from the graveyard by swapping with the torch, I had them all in the first room ready to go, about to go back the spikey corridor. But then, a ghost spawned very close to me, I got spooked and ran into it multiple times and died. Sad life for the rat.
I might not have it in me to make a third attempt. I'll perhaps give it another go after work.
Removing keys after they've been tried to all doors and found wrong, with a little sound effect, would make it more satisfying to carry those wrong keys too.
But, overall, the game feels solid, the light mechanics are interesting and little frustrating without being too overwhelming - as if you take it slow, you can definitely progress with patience - and the spikes are a good deterrent of just running head first to darkness. A really good game!