This trick will fully unlock Dance Dance Revolution Ultramix 4's secrets including the Fifth Power Course.

At the Master Mode menu highlight the following selections with the cursor for atleast ONE SECOND. Scroll quickly when moving from one MODE selection to the other. I suggest waiting for the female announcer to say the name of the mode before moving to the next MODE selection.

BASIC MODE
EDIT MODE
JUKEBOX MODE
PARTY MODE
RECORDS
WORKOUT MODE

After WORKOUT MODE, scroll up to GAME MODE and select it.