Amazing game! Got kinda scared while going into it! Haha
Could find two beacons in three playthrough, but couldn't find the third in any of these.
The sound design is very good; it was essential for creating the whole atmosphere. I confess that I didn't hear the clue about where the third beacon would be.
I didn't find the game that punishing. I managed to make several mistakes even without battery power for the flashlight, and I really had to "try" to die in order to actually lose the game in the last two playthroughs.
You have a great game with a great concept on your hands. I'm sure that if you decide to improve it, perhaps by adding more clues or interactions, you'll have an even better game.
~ Congrats on your entry!