ProxOS

ProxOS

slojanko · March 8, 2024 · Puzzle, Simulation, Education, Sandbox, Programming

ProxOS is free to play — no purchase needed. We track it so you know if that ever changes.

PC
Positive94% · 17
This game is free to play. Get it on Steam →

Screenshots

ProxOS price

ProxOS is free to play — there is no purchase price, on Steam or anywhere else we track. We keep watching it, so if it ever stops being free the price history on this page will show when that happened and what it changed to.

About ProxOS

Experience the life of developers 30 years ago with ProxOS! The simulated operating system offers everything you need to start learning assembly programming. Compete with your friends to solve progressively harder challenges in clever ways.

Featuring:
  • Code written in assembly and executed on the latest 32KHz processor
  • Best in class editor with debugging tools
  • Custom skins and challenges
  • Display support and keyboard input for interactive programs
  • Manual written by your neighbour
  • Online leaderboards without cheaters
  • Overclocking and more? I'm not paid to reveal hidden features

ProxOS — game info

Platforms
Windows
Steam Deck
Playable
Player modes
Single-player
PC Game Pass
Not included

What Steam players say

Recent verbatim reviews from Steam — separate from playze.io community reviews below.

✦ AI summary

ProxOS is a unique puzzle game that simulates a retro operating system where you solve challenges by writing code in a detailed assembly-like language, offering a satisfying experience for those interested in programming and optimization. Players praise the authentic retro aesthetic, engaging puzzle design, and creative freedom to build custom challenges, though the terse documentation and steep learning curve can be challenging without prior experience in similar games like EXAPUNKS. The complexity of the pseudo-assembly language, with requirements like specifying data types, adds depth but m

Recommended Aug 18, 2024
⠀
8 found this helpful
Recommended Mar 17, 2026
ProxOS is the kind of project that quietly sidesteps conventional expectations of what a “game” should be and instead presents itself as a self-contained computing environment disguised as one. Developed and published by slojanko, it places players inside a fictional operating system inspired by early personal computing, where the primary activity is not exploration, combat, or even puzzle-solving in the traditional sense, but programming. From the moment you begin, it becomes clear that this is less about playing in a world and more about understanding a system—one that invites curiosity, patience, and a willingness to engage with logic at a fundamental level. At its core, ProxOS revolves around writing code in a simplified, assembly-like language and executing it within a simulated machine. The experience is intentionally low-level, emphasizing how instructions are processed rather than abstracting them away. You interact with a basic editor, compile your code, and observe how it behaves within the constraints of the system. Success is not measured through flashy outcomes but through correctness and efficiency—getting a program to run as intended becomes its own reward. This des…
3 found this helpful
Recommended Feb 13, 2025
ProxOS is retro aesthetic zack-like coding problem puzzler. You are presented with an virtual computer with programming utilities to solve coding problems in assembly like language. The retro feel is masterfully done, reminding me of Comet 64 while the actual coding feels more like Zacktronics EXAPUNKS. ProxOS leans more into the simulation side and pseudo assembly is more detailed and thus more complex, e.g. the add command requires to specify data type-- addi for integer or addf for floating. The complexity is more taxing, requiring some effort to understand the assembly-like language before attempting to solve problems. I do not think that I would have understood this game without first playing EXAPUNKS because both games have terse documentation. The concise instructions does not work as well in ProsOS because the psuedo assembly language is more detailed. I am a beginner level programmer (I can make a a todo list app in JS) and I have to really think hard to understand the docs. Ultimately ProxOS is a well designed game and a clear labor of love. This is a programmer making a programming problem games for programmers. It's niche, complicated and exceptionally beauti…
2 found this helpful
Not recommended May 25, 2026
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1 found this helpful
Recommended Mar 26, 2026
Cool game, I like programming in assembly, will probably make some more projects (idk maybe BF interpreter or some more games)
1 found this helpful
Recommended Mar 7, 2025
It's a rather open ended puzzle game that is fun to optimize in. There's the possibility to create custom puzzles once you run out and share on discord. I had one of my puzzles part of the game, so if you want to make puzzles for others to solve, there might be some space for you to do so. You get quite a lot of coding space to solve puzzles which without spoiling the reason why might be a bad thing. Programs don't live in memory in the sort of sense that you can write self modifying code. There is a stack, but it's also not part of the RAM but treated as a separate structure and storage by itself. Overall, the puzzles are decent, though I'd loved to see some more data-packed puzzles. A lot of the data to be read is in integer format which is the largest width to be read in one instruction meaning there is little room for arithmetic parallelism. Puzzles range from dead easy (tutorial level?) to quite tricky. At current writing, there is a puzzle that only 2 people have solved. I don't know if it's because of difficulty, interest or lack of players. I've enjoyed my stay here and I hope to make (and play) more puzzles in the future. The discord isn't very active, but the develop…
1 found this helpful

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