Tip for the good ending (spoilers obviously).

[Fracture94]

SPOILERS: I just completed the game by getting the good ending, and i must say, for those who dont want to wait for hours for the old man to show up on the surface, i can confirm that he always appears when the clock marks 23:10:00 to 23:00:00 aprox. Maybe im wrong and it was just a coincidence, but it happened like 3 times at the same time interval.

[Wolarn]

For me the shadow fell asleep somewhere in the cave. When I woke him up, he said that he dreamed of an old man who fetches water. I immediately sent it under the surface, and a short time later the old man with the bucket came. Unfortunately I had not paid attention and went into the fountain a little late. But never mind, I still have to wait for my birthday, and unfortunately it will take a long time.
(Translated with Google)