Ultimate Armor For Megaman:

Start a new game. Highlight Megaman at the character selection screen, then press [Up] two times then [Down] nine times. A sound will confirm correct code entry. Press [Enter] to begin game play with his Ultimate armor. This armor has unlimited Giga attacks.
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Black armor for Zero
Start a new game. Highlight Zero at the character selection screen, then press [Down] two times then [Up] nine times. A sound will confirm correct code entry. Press [Enter] to begin game play with his Black armor.
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Zero's Supreme Slash
Either press Dash + Slash, or press Forward, Forward + Slash. Note: This is the best to finish some of the Bosses.