62. Day and night cycle.

I completely forgot to mention:
It's always night in the dungeons, while it's always day on the celestial level.
Underwater, I think twilight turns into dawn (due to refraction, only morning and evening are visible).

Andrey:
The question of implementation has always been one of the last things on my mind.
I collect ideas, build models.
Someone else will implement them in any case, if it happens.