Yeah, it’s a reasonable take. Personally, I have enough issues with all the systems I’ve tried that I homebrewed enough rules that it’s easier to just describe the rules than reference anything else.
The rules started with the Corporation RPG, which uses 2d10s for skill checks, and you try to roll below your attribute + points in a skill, and the skills are all selected to be genre-relevant.
The combat system is totally custom. I get that it’s kind of risky and hubristic, but I’ll just say it: I’ve never found a combat system that worked for my interests. The most fun systems I’ve played are Gloomhaven and Unmatched, which are both board games, not RPGs. So I made my own based on what I like.
The goal was to make something that had a feeling like fights in real life: it should feel somewhat tactical, but also be very fast and impulsive rather than slow and methodical. The solution is that it’s a played on a hex grid map, and the players have a very simple set of actions: they can move, they have one or two attacks, they can defend, and they can aim. It acts like rock-paper-scissors: everyone picks their action at the start of the round, then reveals at once. If you want to get tactical, there is plenty of room, but generally it should feel like a real fight: if someone has ranged attacks, you want to take cover. If someone is very aggressive, you should probably play defense. If they are very defensive, take advantage by using aim, which doesn’t work if you get attacked in the round you play it, but makes your next attack devastating if you play it successfully. There are some nuances like fudge dice to avoid it all being determination, but overall it feels fast, easy to pick up, and fair.
Personally, it’s my favorite combat system. Which is funny, because the game isn’t that combat heavy, but it’s an example of why I just went ahead and made custom rules system. If i thought I could tell the stories better with another one I would’ve, but I didn’t. So this is what i did.
As you said, it’s FOSG, so people can take the stories or lore and use them in FATE or GURPS or whatever they like. But it started as a game for friends, and I wrote the manual around the game as I ran it.