Hold Left stick Left + Right stick Right. Press , , , , , , ,	Full Health
Hold Left stick Left + Right stick Right. Press , , ,	Fully Juiced Zen Meter
Hold Left stick Down + Right stick Up. Press , , ,	Crystal Sword
Hold Left stick Up + Right stick Down. Press , , ,	Flame Blade

Sketch Gallery:
Beat the game on Easy.

Background Gallery:
Beat the game on Normal.

Model Gallery:
Beat the game on Hard.

Thanks to Revolution readers Samurai Bob and kianti!