Love the theme of stirring a witch's cauldron! Many ways you could expand upon this game if desired. Various types of enemy waves, new spells, maybe even having to balance adding ingredients from around the room to the cauldron and then keeping the stir level at a certain percentage. Almost Cooking Mama-esque? Then you could be scored on potion accuracy at the end of a round.
Also, enjoyed that the game let you keep playing after winning. Got over 2500 before I decided to exit / comment.