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

Evolve energy item
Press Y, Right, Down, B, L, A, R, A, Y at the title screen.

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

Blackagumon
Defeat BlackAgumon in single player mode when he surprise attacks you. He can digivolve into BackGreymon and BlackWarGreymon.

Blackgabumon
Defeat BlackGabumon in single player mode when he attacks you. He can digivolve into BlackGarurumon and BlackMetalGarurumon.

Blackguilmon
Defeat BlackGuilmon in single player mode when he attacks you. He can digivolve into BlackGrowlmon and ChaosGallantmon.

Diaboramon
Defeat Diaboramon in single player mode. He is the Boss fourth to the top and cannot digivolve.

Duskmon
Defeat Duskmon in single player mode. He is the Boss second to the top and cannot digivolve.

Malomyotismon
Defeat MaloMyotismon in single player mode. He is the boss on the top and cannot digivolve.

Neemon
Defeat Neemon in single player mode. He is the boss fifth to the top and cannot digivolve.

Omnimon
Defeat Omnimon in single player mode. He is the boss third to the top and cannot digivolve.

Chaos Wasteland Stage
In single player mode, defeat any of the following Digimon to unlock it: Duskmon, Diaboramon, Omnimon, MaloMyotismon, or Neemon.

Ice Palace Stage
In single player mode, go to the Boss on the bottom. Defeat them to unlock the stage.