Alright. So first off, great work on this thing so far, love the animation and sounds. It is pretty fun, but from reading what you got planned - definitely a long way from completion. Also been checking other people's suggestions in the comments, so it would be nice to see some of them implemented in the future.
Don't rush it though, I understand that we all have lives to go through.
So let's see...
- Customization (i.e. hair style and color, eye color, maybe clothing at some point?). Could do away with adding new characters altogether.
- The cock size increase is a tad bit underwhelming, would love to see the size range increase. I'd also suggest having some sort of warning blocking you off from using more of the red and blue potions, since you don't know the limit until you see it just doesn't do anything anymore.
- Someone else here mentioned they'd like to have optional ballsack, which I agree with - that would be neat.
- Adding onto previous ones about sizes and balls, would be good to add a potion that increases the amount of cum produced. Could make that it also stacks with the size potions.
- Definitely needs a better background than an empty dark void
All in all - love this game and waiting for more. Wishing you good luck with the development!