1. I need at least some of the women to be my type, and have bodies that I think are hot. It doesn't have to be every one, but if all of the girls in a game aren't the kind that I like, then really nothing else matters about it. I'm out.
2. The MC (if male) needs to be an adult, not a kid. He needs to be fit, and of at least average height. And he needs to have a porn star level cock and balls that could exist in real life. Nothing hilariously huge, but nothing tiny either.
3. Its absolutely HUGE for me if the game offers a map where I can pick and choose where I go and what I do next. While purely linear VNs can be good, I still think that every single one of them would be improved with a map. It does a ton for me keeping track of where I am and who all of the characters are.
4. And on that note, character cards! Again, it helps the player remember who everyone is, and I love seeing what all I have done with each one and/or which level they are on.
5. I need the MC to be respectful to the women. Ideally, the MC evolves into a total badass who can seduce women with his charm and good looks.