Big deal you say! well, check this out: this png IS the game. It embeds the executable written in LUA. Try it for yourself - take the png I posted above, load it in pico8 then press escape: voila, full source code, sprite sheet, tracker data, etc. Type "RUN" and the game plays.
Pico8 (and its cousin voxatron) also contain an online cartridge browser that lets you discover and learn from everyone who contributed a cartridge.
Pico-8 is choke-full of these incredible little details that make all the difference. Unfortunately it's not open source itself, which some find a bit odd considering it encourages the open sourcing of the cartridge written for it. Good to see some projects such as TIC-80, LIKO-12 and now PX8 mixing things up a bit, that said it's still a nascent environment and let's not forget it's very much the arbitrary, sometimes amusing limitations imposed by the lead dev that makes these things fun.
I'm pretty interested in open source as a whole, but having pico-8 be a steady stream of revenue has let zep concentrate on it/voxatron, and help do things like maintain the BBS or run the monthly picotachi events to help the community.
Though I wonder if there's more success in a patreon-style model...
But yeah, its a wonderful toy environment, and provides weekly entertainment in my household, where the kids kind of prefer to SPLORE over their other, commercial-based game consoles ..