The style is nice, and the design for plague doctor is adorable!
The gameplay could have used a bit more action, or at least a larger quantity of zombies (though that's just me nitpicking). Potion throwing should have some kind of animation to let the player know that they are actually throwing it, and sometimes the throwing would stop working, but is fixed by moving away from the zombie and then trying again.
As a person who is still new to game development, I can really appreciate simple games like this. Keep up the good work! I look forward to see what games you make in the future!