ScummVM
scummvm.org
scummvm.org
https://www.scummvm.org/old/docs/specs/introduction.php
https://scummeditor.scummbr.com/
https://wiki.scummvm.org/index.php/SCUMM/Technical_Reference
https://github.com/scummvm/scummvm
PDS: Observation: ScummVM seems to be an interesting fusion of some kind of old Forth stack-based machine (which would give it the ability to run on any computer, including disparate early 8-bit machines) and common tools/libraries/functionality that most 2D (or 2.5D) games would need, including but not limited to image processing, animation, sound, moving background graphics, etc., etc.
Anyway, it's a rather interesting way to gain 2D/2.5D game program portability -- on completely different computer architectures... thus it's worthy of more study...
Also, compare to other stack-based languages (https://en.wikipedia.org/wiki/List_of_programming_languages_...) -- including Adobe Postscript...
Wish more of the legends would open source their games (Kings quest?)