Sorry if I didn't reply immediatly, I was gone away. There's some levels were you have some kind of mask wich is used to simulate the dark in the room and the fact you're carrying your torch. You can see that effect in the sanctuary in zelda 3 for example. When you turn off one layer, it just removethat mask and you can see as if you had turned light on without having to use magic to put fire on the torch wich usually stand in the corners on the rooms. I really think it works like a B/W mask where Black is fully opaque and White is fully transparent.
For the sound channels, I used to try to turnsome channels off to simulate the real sound of my personnel snes wich was in some a little broken and didnt play all the the sound channels. By turning one or two channels off, I was able to play my games the way they were playing with my real deffective snes.
By the way, will you consider adding a virtual keybord for the cheat search option. Naming the cheat codes is not rally user friendly currently.
Please forgive me for my english but it's not my native language.
Keep up the good work.
I would really like to thank you for the feedback you give to the users of Zsnexbox.
If you want, I could try to make you a screenshot of the effect of the layer being disabled but I don't really know how to use Imagestack or something similar but I'm going to look for that.