Dark Albion is unlocked once you have completed the credits level of the main game. Dark Aurora is the sixth level of this second playthrough.
Play thought the level as normal, and every time you come to a chest make sure you're the one to open it. Once you have opened three and recieved powerups (not coins or son of chesty) compelte the level and you will recieve the achievement. There are six chests before the 'break' point, and a number after so there should be plenty if you're sharp. Or ask your teammates to leave them for you if playing online.
You can also get this playing in single player (which is easier as the AI seems incapable of opening chests).