Shark, I just want to say that the main reason I believe your games are so good is that they are not too easy.
I have tried some of the commercial games available on line (and they are not really games), and they do not offer any challenge. Basically, you pick a girl, modify her appearance if you want, and then fuck her any way you want.
For the player to develop interest in a sex game, it is necessary that sexual tension be developed and increased in the course of game play.
The player asks himself, "What do I need to do to have sex with her? How can I get her clothes off, kiss her, caress her, convince her to perform oral sex, anal sex?"
These are the same thoughts going through your mind with a real girl. So, as you play through the game sexual tension and anticipation is produced which makes the payoff, when you finally get what you want, much more rewarding.
One suggestion: The acts necessary to get the girl should be reasonable. In some games (not yours) the player might need to turn a certain corner first before she will open her blouse. It would make more sense to have the requirement be to compliment her breasts and caress her breasts through her blouse, rather than an arbitrary act that wouldn't make sense in a real life seduction.
That's my philosophy on sex games for tonight, and I think similar principles apply to all other games too.
Thanks for the great games, Shark. Looking forward to your next.