Notes on Every New System I Play this Year #6: A Perfect Rock

Disclaimer: I encounter many of these systems for one-shots at meetups, where I sometimes won't even know what I'll be playing going in. Because of this, I'll often only have taken a deeper look at parts of the book that relate to character creation, and flipped through the rest. But I'll always have played them!

Played/Mastered on 25.02.2026 with 3 other players and no GM.

A Perfect Rock by Deep Dark Games is a world building game in the truest sense of the word. You play the last survivors of your people aboard a Generation Ship, in search of a new planet to call home–the titular perfect rock. For this, you collect four real rocks, and then use those combined with a few prompts the game gives you as the basis to describe the planets you explore.

Each player gets to choose an aspect to describe, and then rolls for the "essence" of that aspect. So you might choose the "Fauna" aspect, with its essence being that it's "problematic". Your task then is to come up with a description of the planet's fauna, and the reason it's problematic. For both of these, there are only six options each, and all aspects have to be explored for each of the four planets. That's it.

The game itself is very simple, which it can be, because in addition to these two prompts, you of course also get to choose one of the rocks you collected. And rocks are complex. Their features essentially act as a "hidden" third table that multiplies the possible inspirational prompts by an incredibly large factor. It's a genius design that made me think of the way some companies use lava lamps to produce random numbers .

After the first player—the "expedition leader"—describes the first aspect of a planet, it's beautiful how this one fact acts as a gravitational anchor for the rest of their round, with all players almost automatically doing their best to establish their inputs in relation to what came before. This interplay between vast initial randomness and successive network-building quickly leads to very fantastical, but surprisingly internally-coherent planets.

The final step after describing all four planets is to choose one of the planets as your new home. In this step, the fact that you always establish the same six aspects for each of the planets really shines. Because while the initial randomness leads to planets that seem wildly different, this ensures that they are, in the end, still comparable. So you can ask things like "Would we be able to breathe in the planet's atmosphere?" and get an answer for each of them.

The Version

It would be remiss of me not to mention that we didn't play the official version of the game—which is beautiful, and will get a greatly enhanced physical version very soon—but an absolutely incredible version entirely homebrewed by one of my fellow players. So while we used the official rules, our rocks were these perfect, planet-like spheres of different sizes, placed on a board of slate with milled orbit lines, and an actual glowing sun.

The power of the sun, on the board of our game.

Also notice the little slate tablets and chalk pencils in the background, turning this into a "slate & chalk game".

The Pairing

In our session, we played Oh Captain, My Captain! immediately afterwards, using that game to come up with a story surrounding the captain of our Generation Ship. This worked out beautifully, with one game leaning towards collaborative world building and the other more towards creating characters and story telling. But both with no prep or GM, and with only minimal rules.

I think this 1-2 punch would be a great way to introduce people to roleplaying games, packing a huge range of things RPGs can be about in just one evening, while being very low-overhead and approachable.

Loved it. | Liked it. | Didn't care for it.

Cover image: Twenty-One Pebbles