Opus Magnum is a puzzle-based programming game developed by Zachtronics. It was released for Microsoft Windows, Linux, and Mac in December 2017, following about two months of early access. In the game, the player must assemble a series of machines using various tools and program them to complete alchemy-related tasks. The player can advance with any working solution to each problem, but is challenged through leaderboards to produce a machine that does the task in the shortest time, with the lowest cost of materials, and/or the smallest occupied area. Opus Magnum is based on The Codex of Alchemical Engineering, one of the earliest Flash games made by Zach Barth prior to establishing Zachtronics.

Zachtronics LLC is an American video game developer, best known for engineering-oriented puzzle video games and programming games. Zachtronics was founded by Zach Barth in 2000, who serves as its lead designer. Some of their games include SpaceChem, Infinifactory, TIS-100, and Shenzhen I/O. Infiniminer (2009) inspired the creation of Minecraft.