Great game! The visuals are super nice to look at, and the sound design is lovely! I did run into some issues but that's to be expected given that it's a demo lol.
Some issues I had were things like how sometimes items spawned in awkward spots (e.g. behind or on top of the tower and therefore unattainable). And when your inventory was full things wouldn't get added of course, but when you returned to those same items with enough space, they would no longer magnetise towards you. The performance was also a bit of a problem, but you're already aware of that one :P (I did notice it seemed to get noticeably worse at sunrise/sunset, it might help to change the light level in bigger jumps rather than lots of little changes to make it smoother like it is now? Idk I'm not exactly a code expert lol, just an idea!).
Honestly most of the issues I had were very small, the only one that properly interrupted the game was the performance, but it helped once I realised I could sleep through the sunrise/sunsets c:
Aside from all that though, I had a lot of fun! I was surprised by how much was already in the game, it felt quite extensive and the current systems have a decent amount to them :D It was pretty interesting to see the more autumnal area, it's a very good way to introduce new/better sources for stuff without changing too much of the starting space!
I'd like to suggest making it so when you complete a quest you get notified in some way so you can collect your reward sooner and get working towards the next faster! Also something to show which new plots are placeholders so no coins get wasted on them :P (I'm assuming the signposts were placeholders anyway). Also perhaps some sort of settings menu so players can toggle things to help performance?
In conclusion, awesome game, and I had a lot of fun :D I'll cut this review off here as it's already about 3x longer than I meant it to be :0 (whoops)
Edited to add: I just remembered another bug, when you move something out of a chest with a full inventory, the game eats the item D: Thankfully it was only a piece of cotton, but still probably worth fixing :P