List of my favorite role-playing game rule systems

Gene Michael Stover (

created Friday, 2022 December 30
updated Sunday, 2023 February 5

original at

This is vain & pointless

Yes, it is.

The list


I'm not sure this system really exists. If not, then it describes a bunch of systems that rely on d100. These include Chaosium's Call of Cthulhu, TSR's Star Frontiers, & a bunch of light-weight, independently published systems I've stumbled on.

What I like about d100 systems is that I think in percent. (I suspect most people do.) It's easy to think about a chance of success. It's easy for an adventure creator who doesn't know all the groups who'll play his adventure, to state chances of success.

Update 2023 February 5: I've learned that there is a system called “d100”. I guess it was for the Stormbringer roll-playing system, which I haven't played but I remember advertised in Dragon magazine in the 1980s. It required you to calculate a target number, roll your percentile dice, add them to your skill & modifiers... a lot like Cyberpunk 2020 except with percentile dice instead of 10-sided dice. I dislike it.

Star Frontiers

I guess Wizards of the Coast is reviving Star Frontiers in the here & now, the 2020s. I've played it occasionally since TSR released it in the 1980s. I mostly play it solo.

I like the urban parts of the setting, though they were sadly emphasized in only a couple SF adventures published in the 1980s. I didn't care so much for exploring uninhabited wasteland planets.

I like how SF uses d100. It has a skill system kind of like GURPS's (predates GURPS, so it'd be more appropriate to say that GURPS uses a skill system kind of like SF's). Opposite of GURPS's skill system, SF's is too coarse, but I prefer that over too fine.

Tunnels & Trolls

Simple & light-weight. Light-hearted. Great for soloing. And the Deluxe Tunnels & Trolls book (which is a joke on Advanced D&D, I hope you noticed) has a fleshed-out world.

Though I'd like to roll more than 2d6 for skill checks, they get an A for trying something different. And you get to roll fist-fulls of d6 during combat, so that's cool.


You get to roll shoeboxes of d6! And it's urban! I love the setting of Shadowrun.

I usually dislike the magic, but we usually just ignore that when we create our own adventures. Sometimes we leave magic to the baddies only, allowing the player characters to rationalize it as unknown, experimental technology.


I reluctantly like GURPS. What I like about it is that, as advertised, you can do practically any genre with this single role-playing system. You don't need to learn a new system for each genre.

As with Shadowrun and T&T, if I can't have percentile dice, I want 6-sided dice.

Most importantly, it's what my friends prefer. I use the system & occasionally grumble about it, but the rules work & we have a good time. This supersedes my gripes about GURPS.

I have a lengthier list of gripes, including...

In the end, GURPS is my friends's favorite system, & it works without me learning a new set of rules for each genre, so it's one of my favorites. But barely.

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