About the Game
“It is not an exaggeration to say that without alchemical engineering, civilization would not exist.”
Hailed as the most promising alchemist of his generation, Anataeus Vaya has just accepted a position as Head Alchemist of House Van Tassen, the oldest and richest of the city’s ancient Houses. But dangers lurk behind the family’s opulent facade, and alchemy alone may not solve every problem.

Opus Magnum is the latest open-ended puzzle game from Zachtronics, the creators of SpaceChem, Infinifactory, TIS-100, and SHENZHEN I/O. Master the intricate, physical machinery of the transmutation engine— the alchemical engineer’s most advanced tool— and use it to create vital remedies, precious gemstones, deadly weapons, and more.
Design Machines - Design and build machines that carry out alchemical processes using a variety of components including programmable arms, customizable tracks, and more esoteric devices like Van Berlo’s wheel and the Glyph of Animismus.
Open-Ended Puzzles - Compete against your friends and the world to build the simplest, fastest, and most compact solutions to the game’s challenges. Export animated GIFs of your elegant designs to show them off.
Steam Workshop - Make and share your own puzzles with full Steam Workshop integration and an easy-to-use puzzle editor. Play the top user-submitted puzzles in the prestigious Journal of Alchemical Engineering, curated by Zachtronics!
Rich Story - Intrigues and dark plots swirl around the city’s ancient Houses. Alchemists, who hold the power to create almost anything known to science, are highly sought— and highly dangerous.
Solitaire Minigame - Alchemical engineering takes focus and concentration. Take a break with Sigmar’s Garden, an original alchemy-based solitaire game. Every game is winnable, but not every game will be won…
Hailed as the most promising alchemist of his generation, Anataeus Vaya has just accepted a position as Head Alchemist of House Van Tassen, the oldest and richest of the city’s ancient Houses. But dangers lurk behind the family’s opulent facade, and alchemy alone may not solve every problem.

Opus Magnum is the latest open-ended puzzle game from Zachtronics, the creators of SpaceChem, Infinifactory, TIS-100, and SHENZHEN I/O. Master the intricate, physical machinery of the transmutation engine— the alchemical engineer’s most advanced tool— and use it to create vital remedies, precious gemstones, deadly weapons, and more.
Design Machines - Design and build machines that carry out alchemical processes using a variety of components including programmable arms, customizable tracks, and more esoteric devices like Van Berlo’s wheel and the Glyph of Animismus.
Open-Ended Puzzles - Compete against your friends and the world to build the simplest, fastest, and most compact solutions to the game’s challenges. Export animated GIFs of your elegant designs to show them off.
Steam Workshop - Make and share your own puzzles with full Steam Workshop integration and an easy-to-use puzzle editor. Play the top user-submitted puzzles in the prestigious Journal of Alchemical Engineering, curated by Zachtronics!
Rich Story - Intrigues and dark plots swirl around the city’s ancient Houses. Alchemists, who hold the power to create almost anything known to science, are highly sought— and highly dangerous.
Solitaire Minigame - Alchemical engineering takes focus and concentration. Take a break with Sigmar’s Garden, an original alchemy-based solitaire game. Every game is winnable, but not every game will be won…
Screenshots
5 imagesVersion Information
Steam Patch Notes
Official update history
On the site: Build 26115378
Up to date
This update adds a new achievement for the De Re Metallica DLC, "The Way of the Metallurgist", that is unlocked when completing its campaign.
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Today's update adds the following:
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- a Polish translation for the Journal of Alchemical Engineering (thanks Doczek!),
- some fixes for obscure bugs when editing custom puzzles that you've already solved, and
- a hidden config setting, AlwaysReplaceLeaderboardScores, to help players who have accidentally submitted "overlap" solutions to the leaderboards.
This update fixes a few small bugs:
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- Fixed a bug in today's earlier update where the folder picker dialog on Windows was stuck behind the game window (I have three monitors and did not notice, sorry not sorry).
- Fixed a bug where the solitaire music would continue playing when exiting Sigmar's Garden II in the journal.
- Fixed a bug in the custom puzzle editor UI where the blackout overlay was offset incorrectly and had a cutout in the top-right corner.
Today's update adds an in-game option for setting the GIF output directory. Clicking the "SET" button should open an OS-level folder picker dialog, which seems like exactly the kind of thing that won't work for many people, especially if you're on a more esoteric operating system. If you run into any trouble, email me at [email protected] and we can investigate!
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Today's update adds a Russian translation for the Journal of Alchemical Engineering, contributed by TrottingHeart from the unofficial Zachtronics Discord.
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Today's update actually contains a Korean translation of the De Re Metallica DLC, unlike last week's update that only translated the puzzle names and the Journal of Alchemical Engineering. Thanks again to Haxton from the unofficial Zachtronics Discord for this contribution.
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Today's update adds a Korean translation for the De Re Metallica DLC campaign and the Journal of Alchemical Engineering, contributed by Haxton from the unofficial Zachtronics Discord. It also contains the following fixes:
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- Changed the GIF frame to localize the names of metrics, since it already localized the names of puzzles.
- Fixed a bug where the guilder sign (G) was replaced with a dollar sign ($) in the Chinese, Japanese, and Korean translations of the game.
- Fixed a bug where pressing the escape key did not close the new journal issue menu.
Today's update includes the following changes:
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- Puzzles in the journal now have a variety of music instead of a single song.
- Fixed a crash when loading a solution that referenced an input or output that was deleted from a custom puzzle.
- Fixed an issue where the new achievement would only show a progress update when you solved a puzzle in a journal issue that you had previously not solved a puzzle in.
Today's update adds a few small quality-of-life fixes:
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- You can now click on the journal issue name to open a menu that lets you quickly select a different journal issue.
- The current journal issue is now persisted in your save file, so that when you relaunch the game it will be open to the same page as last time.
- You can now press F10 to reload the list of custom puzzles.
- Pressing F10 to reload the current solution should now be much faster if you have many solutions.
- Fixed a bug where scrollbar handles could get so small that they were unclickable.
Today's update adds a new issue to the Journal of Alchemical Engineering.
Volume CVIII, Issue XI: Small-Scale Construction Crafts
While research to support the large-scale building projects initiated by the Great Houses has shown a tendency to dominate today’s alchemical science, a dedicated cadre of independent practitioners has managed to initiate a revival of interest in older, half-forgotten traditions. These particular selected formulations hearken back to a time when alchemists proudly refined everyday tools, common substances, and building materials for anyone who needed them.
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Volume CVIII, Issue XI: Small-Scale Construction Crafts
While research to support the large-scale building projects initiated by the Great Houses has shown a tendency to dominate today’s alchemical science, a dedicated cadre of independent practitioners has managed to initiate a revival of interest in older, half-forgotten traditions. These particular selected formulations hearken back to a time when alchemists proudly refined everyday tools, common substances, and building materials for anyone who needed them.
Today's update adds Portuguese and Russian fan translations for the De Re Metallica DLC. Many thanks to Yuri Nikolai and TrottingHeart respectively!
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Today's update upgrades the game to a newer version of the Steam API, which should fix a crash on Mac when attempting to browse to Steam Workshop from in-game.
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Current Release
Build 26115378
Uploaded Nov 03, 2026
System Requirements
OS
N/A
CPU
2.0 GHz
RAM
4 GB RAM
GPU
1366 x 768
How to Install
1
Download all files
2
Extract the .ZIP file to a folder (use WinRAR or 7-Zip)
3
Run Lightning.exe to play
Troubleshooting tips
• Run Redist/_CommonRedist installers if game won't start
• Add folder to Windows Defender exclusions
• Run as administrator
Download
Direct link available
Archive password
Needed when extracting (WinRAR / 7-Zip) — not a site login.
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View AllDownload Opus Magnum for PC with a direct link or via torrent. Get the full version of Opus Magnum for free. Opus Magnum is a Indie released by Zachtronics.