Well, the one that's coming up next will be "Sexual Fantasy Kingdom vol. 4: Futanari Kingdom" - which is described on my website. It'll be pretty much the same format as SFK3, with different scenes (and I'll probably be doing 8 scenes instead of 7).
At some point, I'll also release a special edition of SFK1, which brings it up to the graphic standard of SFK3-4, and a Guide to the Kingdom of Sexual Fantasies - which would be like a CG collection, with images and text descriptions and back stories for some of the characters and locations.
After that, PINK GALAXY will be a little different. It'll contain a number of probably unrelated scenes, like the SFK series, but I'm going to try to include more animation, dialogue/voice, and maybe some additional features like allowing the user to choose camera angles, unlocking scenes in a gallery, or whatever.
There probably won't be more interactivity in PINK GALAXY, than in any previous games, but I'm not sure yet.
I have a lot of ideas for other games, and some of those projects will be more "game" than just "animation", and I'll always try to incorporate more story. I haven't decided on a lot of specifics yet though.
Who knows what the future will hold?
