Dragon Spirit

Dragon Spirit is an infamously difficult vertical scrolling shooter arcade game that was released by Namco in 1987 and licensed to Atari Games for US manufacture and distribution. It runs on Namco System 1 hardware. A sequel named Dragon Saber was released in 1990, which allowed two players to play simultaneously.

Story
After a millennium of captivity, an ugly serpent demon named Zawell escapes imprisonment and kidnaps Alicia, princess to the kingdom of Mitgult. A young, crafty soldier named Amul is selected to rescue the princess and destroy Zawell. In praying to the gods for strength and courage, he points his sword high toward the heavens. Suddenly he is transformed into an all-powerful blue dragon, bestowed with special powers. Though gifted with a lethal air and ground attack, this is not enough. He must locate and obtain extra powers along the way. The demon has instructed nine of the mightiest beasts to stop Amul before reaching his goal.

NOTE: He actually dies after just three hits, and is also transformed into the biggest sprite on screen (except for the bosses). The powerups which give him more heads may give him more firepower, but they also give him more exposure to enemy fire.