Digimon Rumble Arena 2

Go to the title screen and quickly press the folowing buttons.
If the codes are accepted, you will hear a sound.

Energy item:
Press Y, Right, Down, B, L, A, R, A, Y at the title screen.

Full Evolve meter:
Press X, Right, A, Y, Left, B, L + R at the title screen.

Single-hit kills:
Press Right, Up, Left, Down, A, L + R at the title screen.

Unlockables:
Defeat the following digimons in single player mode to unlock them:

Diaboramon: Beat Diaboramon
He cannot digivolve.

Duskmon: Beat Duskmon
He cannot digivolve.

MaloMyotismon: Beat MaloMyotismon
He cannot digivolve.

Neemon: Beat Neemon
He cannot digivolve.

Omnimon: Beat Omnimon
He cannot digivolve.

Black Agumon: Beat Black Agumon
He can digivolve to Back Greymon and Black War Greymon.

Black Gabumon: Beat Black Gabumon
He can digivolve to Black Garurumon and Black Metal Garurumon.

Black Guilmon: Beat Black Guilmon
He can digivolve to Black Growlmon and Chaos Gallantmon.

Unlock Chaos Wasteland stage:
Beat any of the following Digimon:
Duskmon, Diaboramon, Omnimon, MaloMyotismon, or Neemon.

Unlock Ice Palace stage:
Play in single player mode and defeat the Boss on bottom.