Thanks for playing it, good to hear you like it!
Since you mention music, I take it you made it to the end. Congratulations! :P
Light is decreased whenever a monster is close to the player. There is no way to avoid that, except for avoiding the monsters.
The background is, that the light is the players hope, and the monsters are his fears. Thus, if the character sees is fears, his hope fades.
I have to admit though, that it's not entirely intuitive, we should have communicated better what the mechanics are all about.
Anyhow, thanks again, we apprechiate the compliments and feedback. :)