Steam-Heart's

Only Blondia Varady (nicknamed "Blow") and his sister Fallandia have been spared from the disease and must pilot their fighter ships in order to penetrate deep into the domain of each princess, destroy their war machines, and administer the antidote. Fortunately for Blow, the antidote has been synthesized into his reproductive organ, so that means there is only one way to inoculate the girls.... The player controls the fighter ship through vertically scrolling stages, trying to destroy every ship that crosses its path and reach the end boss. The ship has a primary weapon that can be constantly upgraded by collecting power-ups, and a secondary slot for all sorts of collectible weapons that can be picked up in mid-air. The game features 2P-cooperative gameplay and cutscenes made of still images that explain the plot and depict the protagonist's encounters with each princess.