One idea is make jumping/platforming areas, and have it that while in the area you can’t use items, so no breaking or placing stuff, and can’t use the grapple to cheat. Would give players a reason to get the extra jump and climbing perks.
Another dungeon with X number of enemies spawning in randomly, and having to search till the end which has a boss.
Another being empty, and instead full of traps, spikes, falls into the void that kill you, and has puzzles to solve instead.
And at the end of all them, having a chest with select random loot in it, based on the planet the portal is on. So like lvl 6 would have some Gems, while a Metal World would have lots of iron, and Lush world would have lots of Fiberish Leaves and so on.