This is a fantastic question, a great point to look at.
I agree with a lot of the points already made here, about the same three being usable and how OSR-NSR-ish games interact with it.
However, I do believe there’s a set of three questions that naturally pop up while looking at those games. Both if you’re looking to give it a try or if you’re looking for scrap parts to utilize. I’ll be using the Into the Odd family as a example to them:
1. Who the PCs are?
This is commonly explained in the opening of the game, and reinforced through its text.
- In Cairn, they are hardened adventurers exploring a dark, dangerous forest.
- In Electric Bastionland they are residents of a piratically infinite megalopolis who have turned to treasure hunting as their last option after their enterprises went wrong.
- In Mausritter they are brave mice adventuring in a massive world.
With that answer, you can already know what to expect from the game. What the mechanics will reinforce, on what aspects of the concept they’ll focus on, what truths will be solidified through the rules. In the case of Mausritter, you are small, the world is dangerous, and everything is massive by comparison.
2. What is the system’s focus?
Into the Odd is religiously devoted to speed. Everything is built so that it’s solved quickly and doesn’t drag. Combats last mostly three rounds and more often than not end on the first one. All rules fit on a sheet. There’s no bloat in rolling, every situation is solved in a single roll.
The game is built to be this oiled machine that gives punchy setup-deliver, the jump from situation to resolution is always direct and immediate.
While question one told you what to expect from the game, together with two you’ll know how is it going to feel like.
3. What’s this game peculiarity?
This is the most elusive of the three, but what tells this game from the others? It can be something simple like a small difference from other similar games, or it can be something truly unique that you probably haven’t seen before. Sometimes there are multiple of them.
If you’re just looking for spare parts, your gold is probably here.
In the case of Into the Odd, it certainly is auto-hit attacks. It brings other rules with it (like the multiple attackers rule that was added in EB) that all help deliver the original purpose: Combat is dangerous, visceral, and once it starts, blood flows immediately.
Basically all of its hacks keep it, since even though they have different aims, they still want to keep that danger there. We Deal in Lead more or less added hit rolls back, but too create the danger and uncertainty of primitive guns, which is one of it’s own peculiarities.
Now, those three aren’t as firm as the “Story game Big Three”, but I’m sure everyone goes through them while checking a new game on this space.