Dance Pad Unlockables:
Step on the corresponding arrows at the 'Song Selection' screen to unlock the following modes in the game.

Unlock Boost:
Press Left, Right, Down, Up.

Unlock Hidden Mode (Arrows Disappear):
Press Left, Up, Right.

Unlock Sudden Mode (Arrows Appear at Top):
Press Left, Up, Right (Repeat Code x2).

Unlock Stealth Mode (No Arrows):
Press Left, Up, Right (Repeat Code x3).

Unlock Normal Mode (Turn Off Hidden/Sudden/Stealth Mode):
Press Left, Up, Right (Repeat Code x4).

Unlock Little Mode (Off-Beat Arrows Removed):
Press Left, Down, Right.

Unlock Flat Mode (ALL Arrows are Same Color):
Press Left, Down, Right (Repeat Code x2).

Unlock Solo Mode:
Press Left, Down, Right (Repeat Code x3).

Unlock Dark Mode:
Press Left, Down, Right (Repeat Code x4).

Unlock Reverse Mode:
Press Down, Left, Right, Left, Right.

Turn Freeze Arrows Off:
Press Right, Left, Down, Up.

Cancel ALL Mods:
Press Left, Right, Left, Right, Left, Right, Left, Right.


Unlockables

DDR: Extreme Unlock Codes
Enter the Service mode and move the cursor to Game Options. Hold the 1-Player Down arrow and the service button and press the 1-Player 'Start'. When the Secret menu appears select 'Append' from the options and using the 1-Player buttons input the following codes (underscores should be spaces). Then hold the 1-Player Left and Right buttons and press the 1-Player 'Start'. Select Exit (Not Initialize).

Unlock Songs 1-15:
Input PVAGUPM-UALPOEZ

Unlock Songs 1-18:
Input RVNYIXO-YKAWEM

Unlock Songs 1-24:
Input SQFRXYY-JSBERAH

Unlock Songs 1-27:
Input JHEDXF_-ALZSMSH

Unlock Songs 1-5:
Input JLEDKZT-KOZGDJJ

Unlock Sync, Twinbee, Burnin' the Floor Momo Mix:
Input UBNRXAO-UJGPQQI

Unlock Final Songs Unlock Code:
Input BWUVHBK-KVXFXYA


Unlock Extra Stage
Get a grade of AA or higher on Heavy or Oni on your 'Final' stage to unlock the 'Extra Stage'. When obtained the words 'Try Extra Stage!!!' appear on the screen after the song.