Play as pico and slash your way through the enemy infested areas and defeat the big bosses.
Also pick up hearts from the fallen opponents. You can block some attacks but not all.
Use combo points for hard slashes.
A strategy would be to conserve your combo points until its maxed then use it sparingly.
Use it on bosses so you can defeat them quicker. Try a hit and run strategy.
Jump, Move Left, Right - Arrow keys
Block - S
Normal, Strong Attack - A, D keys