Dustforce

The 4 main hubs of the game have 12 levels (4 normal + 4 Silver + 4 Gold) each and 8 levels of each hub are initially locked. In order to unlock the Silver and the Gold levels, you have to get the respective keys from Normal and Silver levels, with the method explained under The Janitor Possesses the Keys . Upon unlocking the last level of each hub, you will get the 4 respective trophies.

Note that, while you can reach every door in every hub with Dustman, navigating the hubs is easier with Dustworth, whom you can control by entering a door, choosing him and quitting the level back to the hub.

If you are having trouble finding all doors in this hub, please refer to the following video: