Recently, I scooped up Petit Computer on my semi-new 2DS (which is also a rather recent development); and I'm fiddling around a little bit with it's code, SmileBASIC. The title has plenty of examples, and very little explanation as to what it's doing or how. Some of the stuff is taking a bit of fiddling with, but I'm up to most of a title screen, at least. And the premise:
A date-seeded Super Mario-like PGC platformer I'm simply calling "HopNBop." It takes the 12-tiles-high, 16-tiles-wide screen and produces 3 vertical levels of varied terrain and scriptable obstacles through it per stage, in 4-tile x 4-tile chunks. About all I'm planning to sprinkle in so far is moving platforms (horizontal/vertical) and springboards (for reaching from ground-level to top-level, or clearing super-huge pits later in the session).
PetitComp has a good amount of default material in it for core development; and the ability for one program to launch another program means that I can do each of these games within the bigger meta as standalone projects, then just make the metagame to tie them together... or at least that's the idea.
http://www.petitcomputer.com/sample/By chance, anyone else pick up and fiddle with Petit Computer yet?