I think more upgrades are needed, so player could be hooked up for longer time (everybody likes to upgrade everything and anything). It can be new types of mushrooms or some flowers or plants. I'd suggest to add accessories like glasses, monocle, chastity cage etc. for example. You can add secrete scenes or arts if you click right spot in main meny or in the game itself. I hope that my thougths will lead you to new concepts or inspire you to some new cool ideas.