Hey, happy that you like it! Outer Wilds is definitely a huge inspiration, love that game.
You make a good point though. I will add some way to indicate unvisited points of interest, so you will know when you have seen everything. Still thinking about how to integrate this lore-wise though. Let me know if you have ideas :)
And be sure to check back later, I'm adding new features all the time.
P.S. there is now an achievement system that guides you through the existing content, as well as a map with points of interest :)