Thank you for playing and for getting all of the collections! 🥰 The collected stars let you to turbo around the map after you mine them. You can press the F-key to get a boost of speed over the map while you have stardust! 🌠
As for the end game, we totally agree! Over the last two years we've been working on a new full version of the game that will be coming to Steam and Consoles that focus on expanding it even more, including implementing a proper story to follow and an end-game. It's been coming along pretty well, and we're aiming to release it early next year. Maybe it'll be of your interest? 👀