At the song selection menu, press and hold the triangular left, triangular right, and rectangular green buttons all at once. All of the listed songs will disappear, and will be replaced by lettered categories
To reach the extra stage MaxX Unlimited, 'simply' AA your final song (Get a Dance Point Rating of 92.0% or higher.) However, it must be on Heavy, and Little cannot be on (Although any other modifier, including Freeze-Off, can be.) MaxX Unlimited EX is played with 1.5x Speed, Reverse Scroll, Dark Mode, and Pressure Mode ON.
To choose your modifiers hold down the Start (the [Green] button) when you pick your song. It will go to a screen where you can pick everything from speed to difficulty.
Enter these codes on the song selection screen using the pad.
At the song selection screen, step on Left, Right, Down, Up to play in Boost Mode. In this mode, the arrows progressively go faster as they scroll up the screen.