Don't worry if you don't like Westerns. I don't, and I quickly stopped caring that SotM was one. The emphasis here isn't on Western flavor or what-have-you, though there is plenty of it. Like the previous author's Dynamite Powers vs. the Ray of Night!, it's more about MacGuyvering things, though it's a good deal more serious. I have to admit I remembered the silly fun more than the MacGuyvering, so I hoped the second bit held up, and it does. I also felt the path and plot were a bit clearer, which I think is a combination of both experience as a designer and programmer and the more realistic setting. So I was pleased and unsurprised to see it do so well in the Comp.
Things start out pretty badly for you, Boots Taylor. The Black Blade has kidnapped Rosa, whom you think you've connected with nicely, and you go chasing the gang by yourself. Unsurprisingly, you're ambushed, and while you're hiding, a thug named Ace is throwing canisters at you in order to kill you. The higher-up gang members have business back at the ranch, and you're unarmed, so how hard can it be? While ducking, you sort of wonder how they explode, but more importantly, you're wondering how to disrupt him. That's your first puzzle. Once he's gone, you find a small gold casket you find on his person. Operating it is the first real puzzle, and the game is quite kind saying "okay, next time just use (command)!" Earning points is always nice, but earning a shortcut is an extra bonus!
The casket(Spoiler - click to show), which is really a lighter, helps you kill three more enemies: the gang members who left Ace to kill you. They're all hiding so as not to give anyone a clear shot. But that means if you sneak around right, they don't have one, either. Podge sneaks around the corral, Whitey is on the roof of the barn, and Felipe is on a windmill. These locations, along with a stable where you make friends with a horse (a Western trope, but definitely worthy of a Senor Chang "I'll allow it") hold clues how to kill enemies you can barely see.
All three of these puzzles feel to me very smart, yet not obscure. Upon killing each person, you note they didn't deserve quite a gruesome death (I suppose safety ladders weren't invented back then, leaving Whitey and Felipe having to jump,) but you still find a letter and a key in a pocket on each corpse. Each is used to open a triple-lock (spare a thought for poor Ace, who didn't own one) that leads to the Real Mystery.
Given the time frame (just after the Civil War) there are some call-backs to invoking the Confederacy that feel relevant today. Other reviewers pointed them out a bit better. It's all quite a dirty business aside from that. I may be walking a tightrope avoiding what the Real Mystery is, as I'd like to, but I just want to add, I found the annotations at the end interesting. Some stuff, like the safety powder, I knew, and some I did not. I feel like this is a game I could revisit in a year or so, having forgotten a lot of details, and I would recall enough of it to enjoy it unfolding in a slightly different way. Maybe as a boost before any of 2022's longer IFComp games that might seem intimidating. However, if I had to use a walkthrough, I'd be glad to read the one included with the game. It's a story by itself and manages to avoid the mechanical "move here then here" or even the stronger narration/command back-and-forth. I don't think it would've worked nearly as well if it weren't walking you through such a good story. It asks questions about what you may've noticed, then tells you, and it has a few red herrings worth trying. It's great fun, with a lot of care put in.
Oh, one thing: once you finish, the opening scene makes a bit more sense. You'll probably have forgotten it when you've been engaged in the story.