Mega Man X6 Codes and Unlockables (PSX)

Mega Man X6 is the sixth main game in the Mega Man X series by Capcom, and is the first to not be directed by series creator Keiji Inafune. The PlayStation version was released in 2001 in US and in Singapore's AMK Hub in 2007. The game was released for the PC in 2003 as well, but only in Asia. The game was re-released on January 10, 2006 as part of the Mega Man X Collection for the GameCube and PlayStation 2. The story begins three weeks after Mega Man X5, with Zero missing, presumed dead, and the Earth's surface rendered uninhabitable. Rumors are spreading through the Reploid World of a Maverick named Zero Nightmare, a Reploid of pure evil that is spreading chaos throughout the world.

After destroying the Zero Nightmare, X learns that Zero is alive, just recovering from damage sustained in the last game. When Zero is recovered, he joins X and they seek out the researchers who built the Nightmare Zero. X finds the lead researcher, Gate, in his lab. After X defeats Gate in battle, Gate reveals that he has rebuilt Sigma, the leader of the Mavericks. Sigma kills Gate, then challenges X to a duel. X is able to defeat the rebuilt Sigma. (Wikipedia)

Codes

Cheat Code
After you press start, before you select new game, input the following code. You will hear a confirmation sound if you do it correctly.

L1 x 3, R2 x 1 - Enable Dark version of the Revived Hunter.

Left x 3, Right x 1 - Enable Ultimate Armour for X

Unlockables

Nightmare Level Unlockables
Finding a portal in each Nightmare Stage (stages marked in red on stage select).

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.

The opening video of the game's US version: