Screenshots
Watch trailer on Steam ↗Reactonix Sandbox
Dark Games DGG · Published by Dark Games DGG
Last updated 4 Oct 2026
Reactonix is a flexible and enjoyable simulation sandbox where every force is at your command. Create ecosystems alone or with friends, experiment with physics and watch life evolve—or start an apocalypse for the sake of science. Complete freedom to create and destroy is in your hands.
Indie, Simulation, Massively Multiplayer · 2026 · More free games
Explore endless possibilities as you sculpt ecosystems or unleash chaos in Reactonix Sandbox. This indie, simulation game offers complete freedom to create and destroy with friends or alone, pushing the boundaries of physics-based experimentation.
About this game
Welcome to Reactonix!
Create your own worlds—or leave nothing but ashes!
A wealth of tools. Materials, living creatures, forces of nature and much, much more are in your hands. What happens to the world is up to you.
P.S. Most importantly, don't try at home what you do in the game! (=
Forces of destruction. After all, who doesn't need a little fire for fun now and then?
Life — from familiar to alien. From ordinary plants to unimaginable beings and an evolutionary life system that depends on environmental conditions.
Physical processes. Detailed simulation of natural phenomena, down to the ability to control individual cells.
Don't be alone!
Co-op. Invite friends into your world or join theirs to create and destroy together! Or maybe, not entirely together... (=
Workshop. Share your worlds and recorded statistics with the community!
Mod support. The game includes tools for integrating mods into many parts. Create new tools, materials, processes—or something bigger—if you want!
More than just sight!
Multiple view modes. Is it boring to look at the world with only your eyes? Observe temperature, creatures and other processes separately!
Statistics. Ever wanted to feel like a scientist? Now you can rely not only on your eyes but also on numbers and charts!
And remember, EVERYTHING here is under your control! (Unless your friends get in the way. (= )
System Requirements
Will my PC run this? →Minimum
- Requires a 64-bit processor and operating system
- OS *: Windows 7+
- Processor: Intel Core 2 Quad CPU Q6600/AMD A6 3670K
- Memory: 1 GB RAM
- Graphics: Any
- Storage: 500 MB available space
Recommended
- Requires a 64-bit processor and operating system
- OS: Windows 10+
- Processor: Intel Core i7-3770K/Ryzen 3 1200
- Memory: 2 GB RAM
- Graphics: Any GPU with support for DX11 / OpenGL 4.3 / Vulkan
- DirectX: Version 11
- Storage: 500 MB available space
Supported Languages
Latest news
AnnouncementsOfficial
A Letter from the New Year's Simulation
Happy New Year, researchers! During this festive season, I wish you boundless space for experimentation, only confirmed hypotheses, and inspiring results in all your endeavors! {STEAM_CLAN_IMAGE}/45839884/fba19d2ced7d30e520b4717e6cfcca301d42bcf2.png In 2026, the development of Reactonix Sandbox continues. As always, I will share details about the game and talk about what you'll be able to experiment with in the sandbox. See you in the new year 2026!Read full article on Community Announcements (addvans)AnnouncementsOfficial
Materials transforming
Greetings from the simulation! I continue to tell you about the game. Before heading off for the New Year holidays, I'll show you an important element of the sandbox - the interaction between elements. All Three States I've already mentioned that in Reactonix Sandbox, elements are presented in three possible forms - gases, solids, and liquids. During the simulation, substances can change their state - melt, freeze, and thaw: {STEAM_CLAN_IMAGE}/45839884/5b3c4688f807acc499749e82ac486beaf33b0787.gif Almost every element reacts to temperature, even plants. Some of them bloom in cold conditions, although most won't survive at temperatures below 0 degrees: {STEAM_CLAN_IMAGE}/45839884/f2b5d092c99906a7e844f994bfd3aa8161785f52.gif Chemical Interactions In addition to reacting to temperature, substances also react to each other. Thus, metals change upon contact with liquids or air: {STEAM_CLAN_IMAGE}/45839884/9bc738c3348ad779f52c62da98464f81688955f5.gif Liquids can affect more than just metals. A large percentage of the liquid substances in the game are acids, which have a destructive effect on other elements. Some acids break down metals more strongly, others - organic particles: {STEAM_CLAN_IMAGE}/45839884/9a1598b3f0ec121df7d570642e85a3eb2aba0c9f.gif Super-Elements Alongside elements found in nature (and those that will be added by mods), Reactonix Sandbox will feature unique substances. We've written about them before, but now we'll reveal a couple more. For example, a heat-resistant material - this one won't catch fire or melt even under the most extreme temperatures. Great for boiling water: {STEAM_CLAN_IMAGE}/45839884/3a515557b0fa47903889272650cc005039c5b270.gif The best way to support the game in active development is to add it to your Wishlist: https://store.steampowered.com/app/3426670/Reactonix_Sandbox/ And join the game's Discord server - the news will be there too! discord.gg/dgg-gamesRead full article on Community Announcements (addvans)AnnouncementsOfficial
Answers about simulation
Greetings from the simulation! We're continuing our regular development diary. This week, we're answering player questions that have piled up since the start of development. You can ask more questions like these in our Discord community - I'll try to address them! How many elements are planned for the full version of the game? Around five hundred materials, but not all of them will be directly available. Some can only be obtained by combining several "brushes" and conducting various reactions. The number of brushes themselves is planned to be around two hundred. Currently, the game already has over 300 materials and about 100 brushes. Will there be an in-game element editor? Implementing a constructor within the game is not currently planned. However, players will have access to modding tools. You will be able to add your own materials using them. Reactonix Sandbox will support the Steam Workshop - you can share your creations (elements, worlds, statistics) there. {STEAM_CLAN_IMAGE}/45839884/5d0e645e407954730e9c2656c1db531d6361feb6.gif Are complex lifeforms planned - like land-walking animals, humans? Yes, the game will feature animals, including not just land-walkers but also aquatic life. The algorithm for the propagation and existence of life has already been implemented in the game. I will be making it more complex over time. Will there be a mode with a goal or scenario system? No separate mode besides the sandbox is planned for release. But there will be additional in-game goals. They will be presented as achievements and a material compendium that can be filled by analyzing materials in the world. What's the planned player limit for multiplayer mode? The capabilities in co-op mode are the same as in single-player. Co-op supports up to 4 people and is directly linked to Steam - you will be able to connect via the platform's interface. {STEAM_CLAN_IMAGE}/45839884/32fbb07ce87f729bd5df4486ed97d0d8906b0ed2.gif What kind of post-release support is planned for the ga...Read full article on Community Announcements (addvans)
