1. Depends which curtains you mean. The ones before the stair maze are connected to an enchantment, and by extension a treasure room.... but this is after the symmetry level that you’re on. If you mean in general, I’m not sure if they do anything, though I seem to remember a scroll that mentions the curtains.
2. Magic maps are nearly always useful. The runes are for map spells. For instance... ku shows monsters, ros shows fake walls and pits.
3. The pit...
makes a different sound when it opens and closes. Go to the light side to find out which is which.
I should warn you that there is a bug that sometimes occurs on this level. If the dark side suddenly becomes light, that is the bug. It also happened to me where everything went dark on every level. This is also a bug.
The dark side should only become light after you pull the lever at the end. You’ll get a message when it’s done.
Also, you can use bombs for temporary light... but I must warn you that...
you need 6 of them to open the treasure room, and there are only 6 on the level.
You can buy extra ones in the clock tower shop, but they are expensive. I would recommend completing it in the dark. It can be done.
4. No. If you’re playing it windowed you could try it in full screen, but there’s no way to enlarge it.
“Hope I am near the end” - a few levels to get through yet.