For people who are going for the hard badge, note that restarting the game will usually disable the bonus timer in zone 1. So to get those additional points, make sure that you go to the main menu to start a new game so that you can get bonus points.
Just to add to UltimateChaos' suggestion, you can also buy moon shards from the shop at 500 each so that you don't have to grind all of the previous levels.