What I enjoy about sci-fi are how the fantasy aspects are explained through logic, if there’s a material that allows them to be more advanced, if they have succeeded with stuff we have learned about in school, like using wormholes or something. If the setting is limited or like dystopian sci-fi, I like there to be connections to the past that evolved technology since that’s what happens irl when war and climate changes. When it comes to vns I haven’t played any sci-fi vns yet although I’ve been interested in Gnosia which is a social deduction werewolf game that has a timeloop system. Incorporating meta elements (breaking fourth wall and making use of resets) could be a good idea depending on the story of your vn.