This is a very good game. Maybe could benefit from more voice acting and a bit more development for characters in the future. 
Usually it takes like 5-10 minutes to get laid with anyone. I guess it's intentional, but it could be good for variety.
Also, it's strange after you slept with someone, and the next time they love you more that anything in the world. Shifts in dynamics happens too fast(Like with coach). Gradual love or corruption is feeling more natural. A lot more. But with this speed you start to remember that this is not "real people". Always bad sign in any story.
It's cute in some cases. Like with aliens, I can believe that - different culture. Or maybe like one of the girls on the ship.