The Journey of Development
I am a long-time GameMaker hobbyist, therefore I decided to keep developing in GameMaker studio for development speed reasons, while trying to keep somewhat close to the pico-8 look & feel, because I admire the pico-8 games. So I thought "Hey, what can one do on a 128x128 canvas? And how do I include it with the theme 'Depths'?"

So I thought, "depths" can mean two things: the literal depth of the map/world (hence, the underground pyramid), but also "depth" as in: there is more dimension to what you see & interact with.
This led to an idea (word-for-word in my design document):
"You carry a crystal, and the camera follows that crystal. If you fall, you come out of the top of the screen again"
This way, the level itself would gain a whole dimension of depth, because just changing the camera position, the possibilities would change completely.
And by quickly hacking things together (as I usually do), I went from this...
...to this...
...to this!

That's my thought process. How did you come up with your ideas & designs?
(If you like, have a look at DYAMID)