Majuu-ou: King of Demons

Majuu-ou is a side-scrolling platformer for the Super Nintendo that has influences from Castlevania and Contra. You play the role of Abel, who wants to free his daughter from the depths of hell. When you defeat certain bosses, they drop large, color-changing gems. When you pick up the gem, you will transform into either a red harpy, a blue dragon or a green lizard, depending on what color it is when you pick it up. Each type of demon has its own special attacks.