It's weird, stumbling on Adventuron late and still having a backlog of stuff I really want to see. I've seen writers' more mature works first, with the earlier ones coming later. All sorts of factors, then, blunt ambition. The new authoring system is tricky to learn, there aren't resources, parts of the syntax may not be ironed out, and maybe there aren't as many great shortcuts or examples yet. People just want to get a nice game out there. And in the case of SoM, Garry Francis did. And went on to even nicer.
Overall I think the only possible point against SoM is that it is relatively unambitious, as a cave exploration game. As a thief armed only with a knife, you get by a gross troll (a highlight of the graphics, both when it is in your way or defeated for good,) make fire, solve a riddle, and pick off a slightly unexpected treasure. Hence the twenty points in the game, with only four actions. The map is linear. You get in and out. There's a quite sensible inventory-capacity (well, sort of) puzzle.
It's all over a bit too soon. I wondered if I'd really earned the treasure I found, but maybe part of this was due to the nature of the treasure and my enjoying the ride.