I don't think I can have any suggestions or opinion about the game yet since I had only experienced only the basic of it.
The demo is a bit boring. Out of 5 listed features: dig, gather, whack-a-mole, upgrade, and talk. Arguably only the whack-a-mole part is fully implemented.
Gather and upgrade you said won't even be in the demo.
Digging tie strongly to both of those features for reward and further progress so it's really just testing out mechanics right now. Which is quite great, no bug that I can see, little lag, but it's not really a playing feature.
The interactions/visual novel part of the game is still only just "talk to 2 of them and not again".
An interesting idea of using visual novels and digging together as mechanic and plot for the game is maybe the only things I can say. Hopefully I can play it further.