Had an idea for a #Gemini game with real-time space travel, so if it takes days to get somewhere you just have to check back (or wait for a notification).
Fuel requirements would not be realistic though, they'd be more like in The Expanse where ships can be constantly under thrust.
Also, something like a gift economy and no violence, so it is just a bunch of chill geminauts floating around the solar system and doing nice things for its inhabitants