I primarily know Shadowgate from the wonderful NES port, which was ported by some Japanese company and whose Japanese musician composed the beautiful, iconic music which I frankly thought was there all along. This turned out to be false; the original game was entirely mute, save for some ridiculous sound effects. Having only learned about the original many years later, it seemed sterile and dead in comparison.
The original game lists the credits here: https://www.mobygames.com/game/macintosh/shadowgate/credits
David Feldman, David Marsh, Terry Schulenburg, Karl Roelofs, Jay Zipnick, Todd Squires, Darin Adler, Tod Zipnick, Waldemar Horwat, Steven Hays
Sadly, they are all bundled together under a generic "Staff" label; there's no telling who actually did what. Frequently, there are just a couple of actual programmers/designers/graphics artists, with several members of a staff/team just being responsible for the business side and marketing and all that stuff, which really has nothing to do with the actual game itself. (But of course is still very important -- crucial even -- for the game to actually find an audience.)
I've long searched and tried to figure out the "real" credits. I want to know exactly who did what. I don't think that it's ever the case that all these people would sit in a room and "do a little here and a little there"; that's just not how things work. Maybe they would give minor idea input and things like that, but I'm convinced that there must have been a subset of those listed individuals who did the "actual work" for that classic game.
Note that, while I'm also interested in the answer to the same question for Déjà Vu, I primarily am asking about the original Shadowgate for Macintosh and not the other games in the "MacVenture" series.