Hi dreamer1988! I, like others, found this game to just be very slow overall -- not even just the walking speed, though that definitely did contribute to it. But the pacing and the forced exploration is what did it for me. I love the idea of having to find your grandfather / his marbles (lol love that pun, as well), but I think allowing the player a little bit of freewill to explore at their own pace with a little less hand-holding / locking them into specific areas until they've hit some undisclosed goal would go a long way to helping improve that.
The music used was very fitting and lovely. Overall, I think the concept is overall good, but just needs a little more testing to get some input / feedback from different styles of players so you're able to keep fine-tuning it.
edited: hit submit too early!