Unlock the following characters by performing the corresponding tasks:

CHARACTER - HOW TO UNLOCK
Blues/Protoman - Complete all 100 challenges in Challenge mode to unlock Blues/Protoman.
Mega - Complete 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 - Complete New Style mode on the Normal difficulty setting to unlock Megaman C.
Rockman S - Complete 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.

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

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.

Defeat the following Bosses with the corresponding weapons:

BOSS - WEAPON
Bombman - Rolling Cutter.
Iceman - Hyperbomb.
Fireman - Ice Slasher.
Oilman - Fire Storm.
Cutman - Super Arm, Fire Storm.
Elecman - Oil Slider, Rolling Cutter, Ice Slasher.
Timeman - Thunder Beam.
Gutsman - Time Slow, Hyperbomb.
Copyrobot - Same as Robot Master.
Dr.Wily Machine 1 - Varies depending on what it uses.
Dr.Wily Machine 2 - Varies depending on what it uses.
Yellow Devil - Fire Storm.
CWU-O1P - Super Arm, Megabuster.

After completing a level under the normal difficulty setting, Roll will sometimes say "Try your best on the next stage kay." instead of "Try your best on the next stage okay."

Unlike in the original games, each Robot Master now has their normal attack which mimics the original along with special attacks that are new to the game. These special attacks are seemingly unavoidable, but you can actually stop them from executing these attacks by finding the attack's corresponding weakness. For example, you can use the Rolling Cutter on Bomb Man's special attack, the Hyper Bombs on Ice Man's special attack, and the Ice Slasher on Fire Man's special attack.