Cool OSR Rule sets outside of Fantasy

Morning all! Hope this Friday has treated you all well and good so far! I just wanted to kick a question out to all of you; what are some rulesets you all have seen in the OSR that wouldn’t fit within the fantasy genre we are so used to seeing?

The only one that really sticks out in my head is the Black Hack 1e Hack is the Mecha Hack, which is a sci-fi ruleset built around giant fighting Robots and Kaiju going at it. It’s an awesome ruleset and brings some awesome ideas to the front, but I feel like it’s one of the few out there that really breaks from fantasy and goes into another genre.

Personally, I want to see or try my hand at developing a Superhero Ruleset of some kind in the vein of the OSR. Be a good challenge to try at least.

Anything you all have seen that breaks away from the fantasy norm of the OSR? Anything you would wish to that isn’t out there yet?


Stars Without Number and Cepheus are the two big ones I can think of, with SWN taking B/X and Traveller and mashing them up, and Cepheus being a retroclone of Traveller. Openquest (a Runequest semi-clone) also has a science fiction adaptation called “River of Heaven”. Those are the big science fiction ones I can think of.


Mothership is a great-looking and well-reviewed sci-fi horror game and there are plenty of post-apocalypse games out there that I haven’t read. Personally, I would love to find something of a generic OSR system.


It would be interesting to see a Generic OSR system, kind of wonder how it would be done since making a Generic system means having to generate plenty of rules that make the system heavier than it would need to be.

I’ve seen SWN around, cracked it open for a little bit but it didn’t really jump out at me and pull me in.

Warrior of the Red Planet is a fair ruleset, based on the John Carter of Mars style of Swords and Planet Fantasy. A good system that I had thoughts of running since it’s a fair bit on the space fantasy that I like.


You’ve also got BX Mars for Sword and Planet adventure.


I haven’t played it, but Esoteric Enterprises is getting a lot of good talk right now, from the creator of Gardens of Ynn. There’s Dark Streets & Darker Secrets by Diogo Nogueira, which is currently pay what you want and worth it. I think the two games are covering similar genre territory. Goodman Games has Mutant Crawl Classic which is more science-fantasy and gets crazy as hell. I’ve had a couple fun campaigns with it. Also connected to DCC RPG is Dark Trails RPG, which is a weird western. Ynas Midgard’s RPG Blog has a great comprehensive list of OSR games, and he does a good job of listing the different genres as well.


Thank you for the link to the list! I’ll have to read through it to see what it has and follow it.

I’ve heard about MCC, but never was able to play it. I’ll have to see if I can do a One-shot with it. Never heard of Dark Trails RPG, I’ll have to look into it since it might be another Western rule-set I’ll have to use.

SWN’s core mechanics are basically a houseruled B/X with the Traveller skill system bolted on. It’s all systems bolted onto that which are the really interesting parts, from building ships, factions, systems, adventures, monsters, cool technology, trading empires, mercenary companies, etc.

Since OSR is more of a playstyle than a genre, I could imagine that it wouldn’t have to be super rules-dense. Instead of having rules for stuck doors or locked chests or piloting spaceships, the rulebook would focus more on game structure and etiquette. How to ask questions, how to reduce risk for your character, things like that. I could see the six original DND attributes remaining because they are broadly applicable, along with a generic currency C to maintain 1 XP = 1 C together with a rudimentary leveling system.


You’re right, I am currently going through the process of rewriting the Design Doc for my “Knights on Bikes/Kids on Horses” project and what I have laid out is likely the closest I could personally see a Generic OSR rule-set could go since it could allow for easier modding and changing.

I do agree that OSR is certainly a play/game style more than anything else, which would make a Generic rule-set more geared towards “How to play OSR” more than “How to play XYZ genre in the same rule-set” (even though the later would still be present). It would certainly have the tone “How you can make this your own” to it.

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How do we split threads, does an admin have to do that? This is a really interesting topic, it reminds me of the standard currency thread!

I agree that modularity is key for a generic OSR system. We’ve all seen systems split up into modules, but not to the extent that the main system itself can be directly transferred to another setting (because of the base assumptions of what classes or abilities are characters comprised of). The main mechanics themselves could be self-contained modules, from abilities to classes to XP, with the assumption that you can add or remove at will without much work. Like you said, it would be good to have the tone that this is something you should make your own, or even specific guidelines on how to do that.

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Over the course of this evening, I can put together A “Generic OSR Ruleset” post and we can continue the discussion on that one since it would be good to open it up to everyone to hear what they have to say.

You hit the nail on the head about the Ruleset being as modular as possible and (basically) having to divorce (to put it harshly) or separate the rules from a given setting while maintaining the generic/general assumptions that comes with an OSR/D&D-esque rule-set that comes with it.


Just split the thread to talk about this! Let’s see if others have good ideas :slight_smile:

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esoteric enterprises is modern fantasy in the vein of magnus archives/scp/other urban fantasy in media. not sure if that counts but it’s definitely leagues away from the traditional medieval feel of most OSR. uses a very intuitive ruleset for anyone who’s played b/x, 1e, or any of the retroclones.

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Star Wars D6 RPG is old school to me and I have an online collection of the “best of” rules here:

Star Wars D6 Rules Essentials


What about Old School Essentials? The core rulebooks are modular so they can be swapped in and out.

It seems logical to me that you could swap out the Classic or Advanced Fantasy Genre rulebook and insert a different setting like Sci-Fi, for example.

I believe this was the intent and the system was designed with this in mind.


I’m hoping this is the case! I have the boxed set and I’ve quite enjoyed playing B/X+ with it so far. I’m looking forward to future supplements and to seeing more new settings. I believe the author has confirmed a Post-Apocalypse setting is in the works and the Advanced Fantasy rules mentions a future Asian Adventures supplement which will feature the Monk.

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Same here, and with the community we have here with the OSR it’s not outside of the realm of possibility for someone outside of the original authors to write their own genre rules for OSE and publish them under the Old School Essentials Third Party License.

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One of my favorites: The Bat Hack, by Rich Rogers, a hack of The Black Hack to play a minor league baseball season. “The Diamond Crawl” replaces dungeon crawling, it’s a sweet sweet game that’s still in playtesting.