At the main menu, press L1(3), R2. If you entered the code correctly, you will hear a sound. Start a new game and find Revived Hunter. He will be in Dark form.
Easy attack with Zero
Press Attack + Dash continuously with Zero.
Fight Dynamo
Defeat High Max in portals then find another portal to face Dynamo. Note, can be rematched after defeating him.
Fight High Max before Gate's Lab
First defeat Nightmare Zero then find another portal.
Fight Nightmare Zero
Go through a portal in any Nightmare Stage for the 1st time.
Get to Gate's lab earlier
Defeat High Max in Nightmare Levels.
Play as Revived Hunter a.k.a. Zero
Defeat Nightmare Zero.
Play as Zero
Find Zero with the teleporters and fight him. He will join you after he is defeated.
X's Ultimate Armor
At the main menu, press Left(3), Right. If you entered the code correctly, you will hear a sound.
