Yeah, I'm sorry the game lacks some explanation haha. I wanted to make it so the game was understandable without much text, but it turns out there's a part of "luck" to that (based on where you stand), but you have to find ways to make the spaceships run into asteroids (in what I intended, the first spaceship would come and quickly get hit by an asteroid).
The reason you lose matter is probably due to spaceships shooting you.
And yeah, the goal is to absorb things so you can become more massive.
I didnt have much time to do playtesting and comments like yours are really usefull, thank you haha