This is actually pretty good. It's simple, but interesting enough for a short game. The character art is excellent. The smug look on the cat's face after you "deal with" her side effects is priceless. I can imagine this forming the basis for a larger and more sophisticated game.
I think my only real criticism is one someone mentioned before - one of the potions has side effects that are just a variation of another potion. It would have been better if all three were distinct.