I'm not trying to suggest that there's something deficient in the approach, just that it makes it harder to answer the sorts of questions I have. I mostly want to know:
1) What does it mean for PX8 (or any other program) to be "PICO-8 compatible" in this context?
2) Does PICO-8 resemble CHIP-8 only in general concept and name, or also in structure?
To be PICO-8 compatible is to run PICO-8 programs, which are written in a slightly extended version of Lua against the PICO-8 API. There isn't a bytecode that these programs compile to - they're shipped as Lua. The format they're shipped in also embeds sprites, sounds, maps, and music patterns.
The only connection that CHIP-8 has with PICO-8 is that they are systems for making retro games (although when CHIP-8 was new in the 1970s the games weren't retro, of course). CHIP-8 is very low-level, while PICO-8 uses Lua, a scripting language similar to Python or Ruby.
> CHIP-8 is an interpreted programming language, developed by Joseph Weisbecker. It was initially used on the COSMAC VIP and Telmac 1800 8-bit microcomputers in the mid-1970s. CHIP-8 programs are run on a CHIP-8 virtual machine. It was made to allow video games to be more easily programmed for said computers.
