Air Zonk TurboGrafx-16

Air Zonk is similar to other scrolling shooters, but has a large number of power-ups and companion characters. Artistically the game is typically lighthearted, featuring humorous bosses such as a sentient garbage heap and an anthropomorphic boat. The gameplay centers around the effective use of shooting and bombing to complete a stage. At the start, the player must pick a companion character to team up with to perform special attacks. Air Zonk takes on the distinct visual style that is sometimes called "cute 'em up". There are three difficulty levels: sweet, spicy, and bitter.

Companion characters help the main character by attacking enemies and by granting Air Zonk special attacks and occasional temporary invulnerability. Friends can be either automatically assigned, through a fixed order, or can be manually chosen before each level. Each friend can only be used once, and wear the Zonk-style shades to signify that they have been used prior. The friend shows up once a power-up showing a large smiley-face with sunglasses is obtained. The large power-up is triggered when approximately five small smiley faces are collected within a period of a few minutes. The friend will initially act as a Gradius-style option which follows the player around shooting a straightforward, relatively weak projectile. If a second large smiley-face icon is collected, Air Zonk and the friend will combine into a hybrid form, granting a new attack and temporary invulnerability. However this will not occur if the friend is injured, indicated by white clouds of smoke coming from the friend's rear. If the friend is damaged, and a new icon is picked up, the friend will be repaired. It takes multiple hits for friends to be eliminated from the screen completely.

Source: Wikipedia