When the first Civiball got badges, people who already had completed the game, had to complete it again to get badges, because the game reseted when you completed it. I hope this one keeps the progress even if you finish the game..?
When you raise your level up to 100, you get your first star and you will be returned to level 1. You get your second star by raising the level to 110, then the third from 120 and so on... And you will always go back to level 1 when you get a star.