Status Boxes
With the debug code activated, pause the game and press L. Unpause and there should be boxes surrounding the characters. A red box means that area of a body is not necessarily attacking, but is dangerous to touch. A blue box is a normal state. A green box is a blocking state. Press L again for three-dimensional boxes, and press it a third time to get rid of them.

Debug Mode - Japanese
In debug mode you can access a ton of options, including stage select, maximum life, level skip, and others. To enable this mode, enter Option mode and press A + Y + C. Enter the Setup screen and you'll see a new Debug option.

After you've enabled debug mode, you have a choice of several options, including:

Start at Level 200
Stage Select
Max or Zero life
Pause the game.
Hold X + Y + Z
Press Up for max life or Down for zero life
Forward or go Back to different battle scenes.
Forward 1 scene - R + Start
Forward 2 scenes - R + A + Start
Forward 3 scenes - R + B + Start
Forward 4 scenes - R + C + Start
Backwards 1 scene - L + R + Start
Backwards 2 scenes - L + R + A + Start
Backwards 3 scenes - L + R + B + Start
Backwards 4 scenes - L + R + C + Start
You can play all 45 characters in Vs battle.
You can max your characters power out.
You can choose which stage to begin on in story mode.
You can watch the different endings.

Keep Han's Legendary Sword
With the debug code on, play through level one until you get to the part where you meet Valgar. Press R + Start to skip past that scene. When level two starts, both Han and the Undead Hero have Legendary swords!

Note: with the debug code on, Han loses his original boost, but gains blue points by holding the sword.

Debug Mode - American
Go to the options menu. Highlight the DIP Switch option. While highlighted, press and hold X + B + Z. Here is the hard part. While holding these, hold the down button. When the cursor goes down the screen, press the C button on the DIP switch menu as the cursor goes to the top of the screen again. It might take some practice to get this code right. Finally, if you did the trick correct, there will be another option at the bottom of the DIP switch screen. It is called Debug and you must turn it on.

Hidden Arena
While playing in Story Mode, you can get to the arena in stages 3, 5 and 12. To do so, kill all the enemies on the level (including the hidden plants and disfunctional robot on stage 3). When you've done this, jump to the back of the screen (the third row) and walk past the sign. You'll arrive in the arena where you can fight as many battles as you like to build up your stafs.