Hi; a friend and I have been working on a CYOA game/story in Twine.
The plot centers around the main character crashing to a planet in some kind of organic pod and discovering they're some sort of tentacled creature. You make decisions to guide yourself through the world, discover the violent humans who live there, try to avoid said violence, and capture and mind control people as slaves and breeding stock as you grow a small force around you and attempt to discover what "mission" you were supposed to undertake on this barbaric world called "Earth".
Keywords: Mind Control, Impregnation, Breast Expansion, M/F, M/F/F, F/F, Tentacles, Birth
It will always be free to play, and you can download the latest here:
http://www.mediafire.com/file/wfdlsf8lqg99nes/Invasive_Species_0.9.9.html