Your time going through the main story of Kirby and the Forgotten Land will be a pretty standard Kirby experience. It won’t be too difficult, but you will have plenty of levels and bosses to make your way through before taking on the final boss, Fecto Elfilis. In some games, the content would end after beating that boss, besides gathering up collectibles and other side content you missed. Does Kirby and the Forgotten Land have post-game content?
Yes, there is quite a bit more content to Kirby and the Forgotten Land after beating the main story. The post-game begins when you enter the game again, and Kirby and Elfilin return to Waddle Dee Town. During the credits, you will see plenty of pictures showing Kirby and other characters celebrating their triumph, but King Leongar is missing, and you get a slight look at him trapped in a bubble where you originally fought him.
To begin looking for Leongar, you will talk to Claworine, who is standing on top of a tower in the town. A rift will open up and drag you into a new area called Isolated Isles: Forgo Dreams filled with levels that you must complete and find the soul fragments for Leongar to save him. Complete all of this content to get new boss fights against Morpho Knight and Chaos Elfilis.