Great gameplay loop and perfectly on theme!
You have most of the foundations down and from here it's really cool thinking how easy it would be to scale the game up and expand the request list and customer sprites for extra variation. ^ ^
I think the main improvements would be (both of which are sorta intertwined):
- Giving the player some kind of either tutorial or more direct explanation on how the grinding process works.
- More feedback all around, there's a lot of stuff that isn't shown such as how many and what ingredients have been used so far, or that the potion has even been crafted and if so what it turned into.
The only bug I came across and maybe I was doing it wrong but I was never able to actually craft a revival potion, I tried maybe 5 times but it seems to be a super duper low chance someone asks for it so it's hard to test.