The question I'm asking myself today is: How do you reproduce that in a role-playing game setting? Maybe you're using the Fourth World in a DC Adventures game. Or the Eternals or Devil Dinosaur in Marvel Super-Heroes RPG. But you might want his flavor in non-superhero games, because guess what, there really isn't any type of comic he didn't try his hand at. Space opera is covered is Captain Victory, 2001 and the like. Kamandi is postapocalyptic. Tales of Asgard was straight-up fantasy, as was Atlas and about half The Demon. He's done war comics, western comics, horror comics, crime comics, romance comics... So we have enough of a corpus to derive the requirements for a Kirbyverse RPG...
1. Anything goes, the more comic booky, the better. Kirby has given us space gods that dress like WWI German officers and cowboys, death on skis, a lovable red carnosaur, energy crackle over Camelot, an fetal supervillain, and Don Rickles in spandex. Literally anything can happen in the Kirbyverse. When it comes to your plots, let your freak flag fly. Import things from other genres and other games. Be outrageous. Create things based on puns. Kirby enjoyed a good collage, so should you.
3. When in doubt--ACTION! Even Kirby's romance stories had their fair share of action. Every session should include a healthy amount of Clobberin' Time. Characters shouldn't run out a door when they can crash through a window. And destruction should be epic. It's important for a Kirbyverse GM not just to engineer violent encounters (violent, but not gory), but to describe the consequences of that violence in the most entertaining way. Hopefully, your system includes cinematic rules; you're going to need them.
4. Enthusiasm!!! Read the comics Kirby actually scripted himself in the 70s and 80s, and you'll find a level of bombast unmatched in comic book history. No matter what the circumstances of a fight are, characters should always be allowed to make bold statements before it starts. Everything should be blown out of proportion. The pride! The egos! The angst! The despair! All of it. Feel free to give bonuses to the most enthusiastic players/characters at the table. Those exclamation marks should be worth something.
Don't be afraid to think BIG!