Here are the levels. Each of them has one of the four ship parts and a Vorticon Guard or Commander. Each Vorticon guards a keycard needed to reach the level's ship part, instead of guarding the ship part itself. I made each level by first making a size and shape for them, deciding to base them off the map thumbnails, which is why they are so large. Levels in the editor are a lot bigger than they appear! To decide which enemies and obstacles to use, I split them into four themes. I then used the Keen 1 levels for inspiration for the areas.
Level 1: Yorp City (New Yorp City?

)
Shaped like the blue city map thumbnail.
Based on: Border Town, a Red Rock Shrine and Capital City.
Themed around "harmless things": Yorps, Butler Robots, Ice Cannons, and Water.
Water isn't harmless but I wanted something to kill Keen other than the Vorticon Guard,
and Vanilla Keen 1 doesn't use bottomless pits.
Level 2: Double-Environment City
Shaped like the green city map thumbnail.
Based on: Emerald City, Ice City, a Red Rock Shrine, the Garg Shrine, and an Ice Shrine.
Themed around "living/natural things": Yorps, Gargs, Pat Pats, Icicles, Water, Spike Plants, and Strangling Vines.
Level 3: Treasure Dome
Shaped like the dome map thumbnail.
Based on: Treasury, Pogo Shrine, and a Red Rock Shrine.
Themed around "mechanical/weaponized things.": Butler Robots, Tank Robots, Ice Cannons, and fire.
I had to do a lot of research on patches to get the Tank Robots to shoot chains, and to make switch bridges. This was the hardest level to make, but I'm glad it worked out , including the falling block "chain reaction".
Level 4: Vorticon Invaded City
Shaped like the white city thumbnail.
Based on: a Red Rock Shrine, an Ice Shrine, Red Maze City, Secret City, and Vorticon
Commanders Castle.
Themed around "harmful things": Gargs, Tank Robots, Pat Pats, Icicles, Fire, Spike Plants, and Strangling Vines.
In this level, I made a boss fight with the Vorticon Guard where you have to avoid it, Gargs, and obstacles, while collection keycards.
I didn't have time to fill the "secret area" with more stuff because it was getting close to Keen's anniversary. (I spent too much time not working on the levels.) So I just filled a room with a bunch of points.