A couple of issues I've found:
- The Boob Potion doesn't seem to lead to any permanent increase in boob size.
- The Mysterious Rectangle seems to have zero purpose in the game.
- The Flower didn't unlock as a permanent accessory (I may have missed something)
- If you use 5 mana to Cook Stew, clicking it from the Meat, it will not light the fire, unlike clicking the cauldron for the same thing. I did not test this with the vegetables for consistency.
- The "Clean Room with Magic" only covers the initial task, sorting out clothes/rags and still requires dusting/sweeping.
Now a few suggestions (spoilers ahead):
- Given that you have the chance to change Cassandra as the final lesson in magic, and are able to draw "a caricature of her" in your sketchbook, I feel like there should be a chance to get a special scene where she gets bigger breasts, even if only temporary (like the Boob Potion). Also goes for more eccentric transformations with enough sketch practice.
- Being able to get The Ending to drink a beer spiked with a Horny Potion, leading to another special ending.
- Being able to modify yourself with magic, once you've learned the final lesson.
- Perhaps a special effect for storing up excessive amounts of magic.