16 KiB



suckless FPS, the best game ever made, for the benefit of all living beings

Why this game is special

  • Completely public domain (CC0) free softare, free culture, libre game for the benefit of all living beings in the Universe, no conoditions on use whatsoever. All art is original work and licensed CC0 (as well as code).
  • Extemely low HW demands (much less than Doom, no GPU, no FPU, just kilobytes of RAM and storage).
  • Suckless, KISS, minimal, simple, short code (< 10000 LOC TODO).
  • Extremely portable (much more than Doom). So far tested on GNU/Linux PC, Pokitto, TODO.
  • Has completely NO external dependencies, not even rendering or IO, that is left to each platform's frontend, but each frontend is very simple.
  • Can fit into less than 256 kb (including all content, textures etc.).
  • Uses no build system, can typically be compiled with a single run of compiler.
  • Works without any file IO, i.e. can work without config files, save files, all content and configs are part of the source code.
  • Doesn't use ANY floating point, everything is integer math (good for platforms without FPU).
  • Written in pure C99, also a subset of C++ (i.e. runs as C++ as well, good for systems that are hard C++ based).
  • Made to last for centuries without maintenance.
  • Goes beyond technical design and also attempts to avoid possible cultural dependencies and barriers (enemies are only robots, no violence on living beings).
  • Created with only free software (GNU/Linux, GIMP, Audacity, gcc, Vim, ...).
  • Single compilation unit (only one .c file to compile, very fast and simple). No build systems.
  • Uses a custom-made 256 color palette (but can run on platforms with fever colors, even just two).
  • Well documented and commented code, written with tinkering and remixing in mind.
  • Feels like good old Doom.

early previews:




In today's world of capitalism and fascism no one even thinks about doing something without personal benefit and without expecting something in return. Complete selflessness is no longer even considered and if it appears by chance, it is ridiculed. Technology that we are using every day is sadly infected by this mentality.

From engineering point of view our technology is the worst in history. Computer technology is unbelievable bloated, ugly, buggy, slow and inefficient, purposefully designed to enslave people, to invade their lives, to be consumed, to resist tinkering and improvement, by law, force, obscurity or other means. Technology doesn't serve people, it serves corporations on the detriment of people. Principles of good, efficient design and focus on long term values have vanished in the capitalist selfish short sighted mentality of greed which has already infected the mentality of the masses who are no longer even able to see their own abuse and enslavement.

This game is a result of my grief about this deeply sad and frightening state of the world, it is my desperate attempt at showing that something, or rather everything, is wrong. I have put great effort in creating it completely from the ground up so that I could waive my rights to it, give it away to everyone. I think it is a great shame of mankind that since now there has been no such a game completely and truly in the public domain for all people to freely play, for students and teachers to freely study and teach, for artists and programmers to freely improve and remix.

this game is also designed to be truly good technology to the greatest extent possible, with as few burdens as possible to all people, both users and developers. It is designed to last for centuries without maintenance -- by only relying on a C compiler, which is relatively simple and perhaps the most essential piece of software, and by avoiding all unnecessary dependencies, both HW and SW, the game is almost certainly guaranteed to be trivially compilable any time in the future, probably even shortly after the technological collapse of our civilization, which is on its way. It is free and simple, making it modifiable by anyone with programming skills, not just legally but also practically. The game tries to practice the values of good design -- minimalism, simplicity, effectiveness, efficiency, elegance, hackability, openness.

Besides support my project has also gotten a lot of hate, being called backwards, utilizing wrong programming practice, being a bad game to play. Nevertheless it has only been made with love and sincere rational belief in its philosophies. I do not see it as a step backwards, but rather a step in a different, better direction. I believe in my work and that if you judge it with an open mind, you may find something new and revise your view of technology, its philosophy and its future. This game has been made for you and I hope you will find it useful.


Is this running on Doom engine or what?

No, this is my custom engine (raycastlib) based on raycasting, a technique used in Wolf3D engine, but it's improved, e.g. supporting multiple levels of floor and ceiling, so that the visual result is something between Wolf3D and Doom (which was a BSP engine, i.e. a principle completely different from raycasting). I've made the engine with the same philosophy in mind as the game itself.

How is this different from the trillion other retro shooters?

Firstly this isn't trying to look like a 90s style shooter, this IS a 90s style shooter. The code is written in the oldschool language and style, in a custom efficient SW rendering engine, just like in the old days, meaning this will run anywhere.

Secondly this is more than a game and is not made for any profit but for the benefit of all people. This is not a product of capitalism, but a manifesto and a selfless work of art. The code and art are free as in freedom, meaning you can do anything you want with them -- you don't have to buy this, agree to any terms, nothing is hidden from you.

Isn't this backwards? The graphics looks like shit.

I wouldn't call this backwards, but rather a different, better direction than which the mainstream technology is taking, though this involves taking some steps back to before the things started to go wrong, which is why the result looks like from early 90s, but from there I am trying to go forwards in the new direction.

The new direction is towards minimalism, simplicity, accessibility ("openness", portability, low HW demands, low education demands, ...), low maintenance cost, being future-proof, helpful to people at large and so on. Such SW is sometimes called suckless or countercomplex.

Why go back to the 90s and not further? Early 90s is roughly right before PCs and games started becoming "too popular" and before comsumerism started deeply infecting and destroying the technology itself, i.e. before programming languages such as Java or platforms like MS Windows became wide spread. At this time games were still written in C (a language invented by science, not capitalism), used software rendering even for 3D, didn't use bloat such as multithreading etc.

What we perceive as good graphics is heavily dependant on what we've learned to perceive as good graphics, and it's more about aesthetics than things like resolution or polygon count. Doom looked amazing when it came out and it still does today to people who didn't let the industry teach them that good graphics equals super HD with realistic shaders requiring the latest and most expensive GPU.

Shouldn't games simply be fun? You're complicating everything with ideological bullshit when it's really just about entertainment.

Games should definitely be fun to play, but they are still technology and engineering art. We have more than enough games that are trying to be just fun before everything else, but practically none putting a little more emphasis also on other aspects -- projects that don't spend all the effort on the shallow shell, but care equally about the insides and the wider context of the world they exist in. I think we need many more games like this one.

Why aren't you using "modern" programming (C++17, Rust, OOP etc.) or "advanced" engines?

Because this "modern" technology is an extremely bad choice for building long-lasting, accessible programs. New languages are a product of capitalism, evolved by the markets to serve corporations to make quick profit, not fulfilling the values that are good for the people.

This game is suppost to be accessible, i.e. require only as many resources as necessarily needed, in order to run and compile even on "weak" and minimal computers, and to run long in the future, which is ensured by dropping dependencies and only relying on a C compiler, which will probably always be the highest priority piece of SW. After the technological collapse a C compiler will be the first SW we'll have to write, and with it this game will basically immediately be compilable.

But you're using python scripts, Javascript for the web port, the PC port depends on SDL etc. Don't you contradict yourself?

No, all these are optional. The core doesn't have any dependencies other than a C99 compiler. Frontends do depend on external libraries, but I've designed the frontend interface so that it's extremely easy to write one, so if let's say SDL dies, it's no problem to write a new frontend using another library.

Python scripts are only simple helpers for converting resources, which aren't required during compilation or code modification. In case python ceases to exist, the scripts can easily be rewritten to another languages, they're fairly simple.

Why aren't you writing in assembly then?

Because assembly isn't portable and even a portable assembly would make it too difficult to write a game of this complexity. C is about the minimum required abstraction.

So I can do anything with this for free? Even like sell it and stuff?

Basically yes, since I have given up all my IP rights, legally you can do anything with this which is not otherwise illegal, without needing any permission from me, which means you can play this, modify this, sell this, without even crediting me. That is all legal, however that doesn't mean it's automatically moral or that I endorse everything you do. As an anarchist I don't want law involved and I feel it is your responsibility to decide what is moral behavior.

If you for example start selling this and make big money, it would be nice if you sent me some of it -- I can't and won't enforce this, I trust you and leave all this to your conscience. Similarly if you modify this, I believe it would be nice if you keep it in the public domain under CC0, but I don't enforce this (if I wanted to, I would license this as copyleft).

Am I so stupid as to trust complete strangers to not abuse this? No, I know some will probably "abuse" my work, but it's a price I am willing to pay and I think the good will be greater than the bad. I believe no one should be able to own information.

You sound like an insane person, are you crazy?

I do have mental issues, but they don't affect my reasoning. I ask you to critically think about ideas I present.

code guide


source files

portability, only backend, avoiding dependencies

how to port to new platform, frontend, configs in files

All global identifiers of the game code start with the prefix SFG_ (meaning suckless FPS game).

The engine -- raycastlib -- works on the principle of raycasting on a square grid and handles the rendering of the 3D environment (minus sprites). There is a copy of raycastlib in this repository but I maintain raycastlib as a separate project in a different repository, which you can see for more details about it. For us, the important functions interfacing with the engine are e.g. SFG_floorHeightAt, SFG_ceilingHeightAt (functions the engine uses to retirieve floor and ceiling height) and SFG_pixelFunc (function the engine uses to write pixels to the screen during rendering, which in turn uses each platform's specific SFG_setPixel).

integer math

sprites 1D zbuffer

The game uses a custom general purpose HSV-based 256 color palette which I again maintain as a separate project in a different repository as well (see it for more details). The advantage of the palette is the arrangement of colors that allows increasing/decreasing color value (brightness) by incrementing/decrementing the color index, which is used for dimming environment and sprites in the distance into shadow/fog without needing color mapping tables (which is what e.g. Doom did), saving memory and CPU cycles for memory access.

All images in the game such as textures, sprites and backgrounds (with just a few exceptions such as font) are 32 x 32 pixels in 16 colors, i.e. 4 bits per pixel. The 16 color palette is specific to each image and is a subpalette of the main 256 color palette. The palette is stored before the image data, so each image takes 16 + (32 * 32) / 2 = 528 bytes. This makes images relatively small, working with them is easy and the code is faster than would be for arbitrary size images. One color (red) is used to indicate transparency.


rng, produces all byte values


map format

main loop, constant time step

optimizations, move computations to compile time, approximations (taxicab, ...), precomputations, -O3

usage rights

tl;dr: everything in this repository is CC0 + a waiver of all rights, completely public domain as much as humanly possible, do absolutely anything you want

I, Miloslav Číž (drummyfish), have created everything in this repository, including but not limited to code, graphics, sprites, palettes, fonts, sounds, music and texts, completely myself from scratch, using completely and exclusive free as in freedom software, without accepting any contributions, with the goal of creating a completely original art which is not a derivative work of anyone else's existing work, so that I could assure that by waiving my intellectual property rights the work will become completely public domain with as little doubt as posible.

This work's goal is to never be encumbered by any exclusive intellectual property rights, it is intended to always stay completely and forever in the public domain, available for any use whatsoever.

I therefore release everything in this repository under CC0 1.0 (public domain, + a waiver of all other IP rights (including patents), which is as follows:

Each contributor to this work agrees that they waive any exclusive rights, including but not limited to copyright, patents, trademark, trade dress, industrial design, plant varieties and trade secrets, to any and all ideas, concepts, processes, discoveries, improvements and inventions conceived, discovered, made, designed, researched or developed by the contributor either solely or jointly with others, which relate to this work or result from this work. Should any waiver of such right be judged legally invalid or ineffective under applicable law, the contributor hereby grants to each affected person a royalty-free, non transferable, non sublicensable, non exclusive, irrevocable and unconditional license to this right.

I would like to ask you, without it being any requirement at all, to please support free software and free culture by sharing at least some of your own work in a similar way I do with this project.

If you'd like to support me or just read something about me and my projects, visit my site: