Presentation is top! And the theme was nicely respected. And making a multiplayer game in 2 days deserves nothing but praises! But I have some criticism to say for that game. I believe the Camera to be too zoomed in and that there is either, way too many planets, or, the gravity is way too violent.
But the concept is really really cute. And since I really like that concept and you seems to want this to be a long term project. I'm gonna be a bit presumptuous and try proposing a different approach to that idea.
I believe the gameplay is too energetic and the scale is way too big for that game to work as intended. The chance of finding someone's constellation are really low! Perhaps having a gallery with all constellation that have been found with some sort of "like" system could work best. As for the "Explore the cosmos together"... I felt a bit lonely in that game. The only thing that reminded I was in a multiplayer game was the "last constellation found" above my screen. Having a minimap with arrows pointing to player's constellations and/or other player could maybe work best. I'd say scrap that gravity mayhem and replace that with another less tiring gameplay loop with a tchat system.
I think you could get some inspiration from that game https://ynoproject.net/2kki/ You explore a dream world with your friend which is a similar setting in a way.
I wish you the best with that game!