Is it not staying dark?
No, it's dark, which isn't the intended goal.
Starting Landmass: Intended to be dark, positioned farthest away from the planet's sun.
Ending Landmass: Intended to be sunny, positoned directly underneath the planet's sun.
There is a teleporter between the two Landmasses. There are two acts currently: Act 1 is talk-to-character, Act 2 is go-through-teleporter.
If the player ignores the goals of Act I, Starting Landmass is dark, Ending Landmass is sunny.
If the player completes Act 1 and Act 2, Starting Landmass is dark, Ending Landmass is dark.