I can only find 3 potion effects:
Red+Blue+White: Larger breasts (3 doses max)
White+Green+Yellow: Cow Girl (2 doses max; one gives tail, one gives horns, order is random)
Pink+Yellow+Cyan: Blonde Hair
I think a logbook to keep track of what potions you have tried and what they do would be a nice addition. Also, if enough potions are added, maybe make it so that the order matters. Or at least, for things like the cow girl, with multiple possible effects that stack, make it so the order of the colors can make the order of the transformation non-random.
Other than that... I think you've got a decent prototype here, but will need a LOT more content for me to determine what the rating should be.