I’ve read the ZIL overview from Infocom, but I feel like what’s lacking is a solid overview/reference for the language. Surely such a thing exists, for the language to be reimplemented. Is it accessible anywhere?
There isn’t a thorough overview right now. Your best bet is a combination of:
Someday, when the “ZIL Language Guide” is more fleshed out, that will be the guide you’re looking for. I started working on it the other day, but then this happened…
…and now I’ve written ZIL syntax highlighters for Pygments and Atom, but not one more word of documentation. C’est la vie de logiciel.