A downloadable asset pack

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Here at Gem Room Games we pride ourselves on our game design work, whether we're modifying modern classics like Blades in the Dark and Macchiato Monsters or starting from scratch with games like Neutron Axe. We're compiling this original work in a series of Technical Manuals, made available via CC BY 4.0 license to other game designers. That means they're available to you, for free, to include in your own games with attribution!

This page is where you will find additional volumes of the Gem Room Games Technical Manual as they are released, alongside devblog posts for any additional designer commentary. Download the pdf for digital reference, or print your own and fill it with notes. If you use any of these designs please let us know in the comments below or on twitter @gemroomgames!

Included in Volume 1

High Magic Lowlives Magic System - A domain focused magic system that is powerful, versatile, and unpredictable.

Neutron Axe Damage System - A fantasy and science fiction damage system that uses dice odds to make light, medium, and heavy weapons feel different and viable.

Subway Runners Modular Monsters - Procedurally generate unpredictable monsters with descriptive clues tied to their abilities, fostering improvisational play without advanced prep.

StatusIn development
Rated 5.0 out of 5 stars
(16 total ratings)
AuthorGem Room Games
TagsDice, mechanics, Tabletop, tech, techjam, Tabletop role-playing game


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Click download now to get access to the following files:

Gem Room Games Technical Manual Volume 1.pdf 98 kB
Gem Room Games Technical Manual Volume 1 - printer friendly edition.pdf 191 kB

Development log


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I was looking for good reading material about making rpgs. This was what I needed. Concise, thoughtful and interesting!


An absolute STEAL at $2