Really nice usage of the theme and very good use of aesthetics/atmosphere. (+Bonus Minecraft villager sound ;O)
What's lacking though is in gameplay, doesn't provide much of any challenge, and keeps being the same. To improve you could make the shop become more messy and disorganized the more you trade.
Having different mechanics like potion brewing of 2 different colors to make a new one that was ordered. Maybe have the different items on the shelf somehow rumble and scatter, though earth shakes or other means, making a mess that you have to reorganize again.
Basically making it a game about ever-increasing orders coming in and with the shop slowly becoming in more disarray.
Other small things include adding background music and making mouse sensitivity higher (Idk, maybe it's just my sensitivity?)
Otherwise a really great game! :D