First off, I love your game. You've obviously learned from the tropes and the predictable plot elements and it is refreshing to have a story that takes a more laid back approach. Well done. At the point when I am playing, most of the action is taking place in the pub. Now that I think of it, All of the action is in the pub. I'm assuming that this will change and that there will be quite a lot more going on in a lot of places.
Correct me if I'm wrong, but I'm guessing that the pub sex scenes and the Simon sex was easy, because you could make the action universal. With Simon, you know that the characters will all look identical (and be naked) and in the pub you know how they will be dressed and don't show anything customized. I'm betting that you would have to make art for every single combination of eye color, hair style, clothing, etc. in every position and that is a LOT of work.
You could do a lot of extreme closeups. Like, you can draw a wide eyes surprised face, or ahegao and just insert that as an accent. That way, you can just re-color the eyes and have some kind of variable check so the program knows which color of eyes the character has. You could also get so close on the sex that it would apply to any customization. Then you just need to account for skin color.
I personally want to see more blowjobs.
I also want to see the option to be flirty or to tease. As confidence goes up, it would be nice to see her more courageous to express her emotional state. Confident plus happy means singing and dancing, Confident plus angry is bitchy and snippy. This would make advanced players need to control their emotional state.
Last suggestion would be the occasional event where the character gets caught while changing or in the bathroom. Even if it's just some guy taking a picture with his cell phone in the park.
Anyway, your game is solid. I'm eager to see what comes out next. Keep going.