Thank you for your feedback :)
For the loop theme, everything loop around the planet where you dig gems but I may agree that as Asteroids leave the screen while orbiting, its less clear that they do. But it was the best for the gameplay and to not overload the player with informations.
Each time you dig a gem, a single new one appear on the planet. It dont move. The increasing difficulty comes from the fact that orbiting asteroids (and the more and more there is) block your sensor. So you might go pass the gem. If you take full loop around the planet without searching efficiently, it works but it takes time so that mean less point