Okay, I played the demo again and I can stated that the main problem with Alan face, besides some strange expressions, is the eyes. Same with Elie's model picture here. Their eyes are kinda alien, I don't know. I think changing them for a more ordinary color, will help a lot. And also, if you're redoing Alan's model, maybe you could increase his tits size? He has already a big butt, but I believe in MAN BOOB supremacy, haha.
And, in regarding of the story, I thought of two options:
If you want a simple story: the MC gets inform of this "Casino" (or something) that, for money, you can play in 1on1 session with some guy, that works there, and if you win, you receive a special treatment, like a happy-ending massage, sorta. And after that, you can go on dates and develop your relationship with him.
If you want a longer/complex story: in this scenario, the MC is informed of a Tournament of Blackjack. So, you have your first encounter with Alan, and if you win, you face the next character (Dean, for example). As the days go by within each match, you get the chance to meet and develop your relationship with the guys you win matches against. There may also be a point system; let me explain my idea: you date, and if you answer correctly, you earn points. But also, you can replay the match with the guy in the same scenario, and see the same sex scene again, to earn more points. And when you earn enough points, you can play another match, in another setting, with different dialogue and a different sex scene, further developing your relationship.
I don't know if I explain myself correctly, but I hope so. And if this helped you in any way, fantastic. Keep up the good work.
PD.: if you will add more characters in the future, I will love to see a guy that is like Olivine from Nu:Carnival: a chaste/priest character that is so kinky but is so repress that he can't accept his "dark side". Also, Olivine has big tits, a big butt and a very summisive personality, haha.