What are the quest reward items??

Regarding the time and hidden quest items you mentioned, there don't seem to be any specific rules in Silvaluca. This game primarily focuses on timed collection within stages, so perhaps those items are random surprises hidden in the corners of the stages? If you discover any clues during your exploration, please be sure to let me know so we can investigate the mystery together!

I haven't received it either~ so I can't help. Pushing for visibility.

Never got one.