In 11/2002 interview with the game's designer Teruhiko Suzuki & general director Masahiro Sakurai published in Nintendo Dream, Suzuki stated that his team began the game's development last summer, by making prototypes to decide if Kirby's sprite should look bigger or smaller than how he appears in Kirby's Adventure. Sakurai expressed uncertainty about the graphics, including the backgrounds. He wanted to improve them so "today's gamers wouldn't find them embarrassing", and the developers ended up redesigning the backgrounds from the ground up in CG. On the other hand, he felt confident that Kirby's new sprite looked "just as good as something you'd see in a modern game."
Contributed by ProtoSnake