How does the Pico 8 work? You pay for the console and the games are included?
It's pretty easy to build your own tools to generate the format, if you were inclined to build an IDE or something along those lines.
https://www.lexaloffle.com/bbs/cposts/un/undune2-3.p8.png
Also note that there is a "Code" button under the game window which shows the full source code.