Everyone keeps saying that to open the POWER CENTER, you need to open every door to every area, then go back to the HUB (Area 1, Main Room). Well, they are WRONG! What you really need to do is defeat The Radish Ruins Boss (Dark Meta Knight). After you defeat Dark Meta Knight, It will show a screen of a room (The Power Center) appearing in the Top left corner of the HUB. What powers are in there, you may ask? Every power except "UFO" and "Master."