Unlockable Characters:
Unlock the following characters by performing the corresponding tasks:

Blues/Protoman – Beat all 100 challenges in Challenge mode to unlock Blues/Protoman.
Mega – Beat all levels on Hard difficulty to unlock Mega. He is Megaman in his basic helper clothes and attacks with a kick. To choose him, select Megaman at the character selection screen and use the menu that appears to play as him.
Megaman C – Beat New Style mode on the Normal difficulty setting to unlock Megaman C.
Rockman S – Beat New Style mode on the Easy difficulty setting to unlock Rockman S.
Bosses – Defeat a Robot Master in New Style mode using only the Mega Buster or Rock Buster to unlock that Boss as a playable character.

Charge Shot/Sliding move:
Beat the game on the Normal difficulty setting to unlock the Charge Shot/Sliding move.

Alternate title screen:
Defeat any Boss in New Style mode. Use that Boss as your character and load the game to have the corresponding person at the title screen. Defeat all Bosses in New Style mode and select Megaman as your character to have all characters appear.