Kirby is the hero of the game and controlled by you, the player. Besides being able to walk and jump through the Stages, Kirby has the unique ability to inhale his opponents and either spit them out again, taking out other enemies, or swallow them; swallowing certain enemies lets him acquire their abilities (known as Copy Abilities). While he possesses one, the Copy Ability's attack replaces his inhaling powers. An ability remains with Kirby until it is discarded (with the button) or he gets hit. Both events cause the ability to bounce away in form of a star; if Kirby inhales and swallows it before it vanishes, he regains the ability.
Another unique skill is Kirby's power to puff himself up at any time, allowing him to fly; he can bypass some sections of Stages this way, but cannot inhale or use Copy Abilities while flying in this manner. Kirby can also swim and remain underwater for an unlimited time, but being submerged keeps him from inhaling (replacing the power with a squirting attack that can be aimed into the four cardinal directions) and limits the effectiveness of his Copy Abilities.
Kirby's five friends can be freed from bags found throughout the game. These bags are guarded by mini-bosses (or sometimes regular enemies) and can only be opened by defeating the opponent standing sentinel. Kirby may pair up with any of the three Animal Friends (Rick, Coo and Kine) in order to gain their respective special skills and enhance his own Copy Abilities; each Copy Ability/Animal Friend combination results in a different, unique power. Animal Friends remain with Kirby until they are sent them away ( while not possessing a Copy Ability) or they lose all six of their health points. Other friends benefit Kirby in different ways and can only be encountered under certain conditions.
Rick the Hamster
Rick is the first Animal Friend Kirby encounters, first appearing in the second Grass Land Stage, where Efreeti has captured him. Riding on Rick's back allows Kirby to progress a little faster on land and keeps him from slipping on ice, but makes him unable to puff up and fly.
Coo the Owl
Kirby's second Animal Friend, Coo, debuts in the first Stage of Big Forest, the second Level, where he can be rescued from a Scarfy. Coo enables Kirby to fly at a greater speed and with better control over his movements, as well as allowing him to inhale or use Copy Abilities while flying and overcome strong wind.
Kine the Sunfish
Kine, the last Animal Friend introduced in the game, makes his first appearance in the second Stage of Ripple Field, the third Level, where Master Green is holding him captive. Teaming up with him lets Kirby swim faster and against strong water currents, as well as inhale and use Copy Abilities to their fullest potential while underwater. Kine is slower on land, however, and cannot fly.
Gooey is a friendly blob of Dark Matter. If Kirby defeats a mini-boss and is already accompanied by the Animal Friend it is usually guarding, the bag contains Gooey instead. Although Gooey cannot accompany Kirby on his journey, "collecting" him restores one bar to his (or his Animal Friend's) life meter.
Blob is Gooey's girlfriend. On very rare occasions, she may be found in a bag that should normally contain Gooey and, like her boyfriend, can be "picked up" by Kirby instead of accompanying him. Finding her is mandatory in order to achieve 100% completion; she counts for exactly 1% completion status.
(Note that Blob is exclusive to the PAL and North American releases of the game; in the Japanese version, her role is filled by a young girl named Chao, a character from Famicom Mukashibanashi Yūyūki who makes a cameo appearance in this game.)