Okay, I made a choice guide here to explain how the different endings work and how to get them. (°∀°d)
Right now there's no real "routes" or wildly divergent story paths. All three chapters so far are essentially character concepts to see how people like the love interests and the setting. Each character has a 2 sex scenes and a "Declined Sex" scene. If you've seen those then congrats! You've got all the endings so far!
The full game is currently in development and I hope to be able to branch out more with each character's individual stories as each character's route takes shape.