Yeaaah it was a bummer that we didn't managed to add sound effects to the game :(
About the main menu bug, we were having a hard time with the game build, and we think that this particular bug has something to do with it.. Unfortunately, we couldn't find time to fix by the deadline. I hope that this did not ruined your experience with the game whatsoever! From the tutorial, collecting the healing asteroid should send you back to the main menu, so I guess this could be another bug that we may look afterwards..
Thanks you for playing!