Fun Fact: Kirby's Adventure was one of the largest games ever made for the system at a whopping 6 megabits.
Kirby's character premiered on the Game Boy and was popular enough that Nintendo gave him this shot on the NES. Kirby's Adventure is a platformer with seven worlds, each of which is broken into several levels with a boss fight, following the basic side-scroller formula that Nintendo had so well-established by 1993. There were also plenty of mini-games and side-activities that could give the player extra lives and new powers.
The defining mechanic of Kirby's Adventure was Kirby's ability to eat things and either spit them out as weapons, or digest their powers and abilities. He could also gulp in air to keep himself afloat. Because Kirby's Adventure was released so late in the life of the console, all the graphics tricks engineers had figured out for the NES resulted in this game having fantastic visuals, some of the best on the system in the eyes of many critics.