On September 16, Kodansha Game Lab launched the Steam store page for “Legacy Code,” a physics simulation game developed by indie game creator Room 127.
No matter the combination, it’s guaranteed to “move”! The unpredictable synergy created by the Marionette Engine
This physics simulation game lets you freely assemble and animate mysterious creatures called “Mechanimals” using everyday objects—such as doll heads, electric fans, televisions, dentures, and cacti—as parts.
The game’s key feature is its proprietary physics engine, the “Marionette Engine.” No matter how bizarre the combination of parts, the creatures move without breaking the physics, resulting in unpredictable Mechanimals whose behavior even their creators can’t foresee. One of the unique joys of this engine is seeing a creature you intended to build walk in ways you never imagined.
The gameplay cycle consists of three elements: “Build,” “Fight,” and “Collect.” The more you repeat the loop of adventuring with your assembled Mechanimals and acquiring new parts through battle, the larger and more powerful your Mechanimals become, and the explorable world itself—including deserts, snow-capped mountains, and ruins—expands.
If you win a battle, you’ll obtain parts from the opponent you defeated. You’ll gain more legs to support your body, your arms will reach farther, and your attacks will pack a heavier punch. Start with a small collection of junk, and eventually grow your Mechanimal into a colossal creature you’ll have to look up to.
Parts come in a wide variety, including character figurines, electric fans, televisions, 3D puzzles, dentures, chains, and cacti. Each part has a unique appearance and movement style, and depending on how you combine them, the Mechanimal’s appearance and behavior will change dramatically.
This title has also been selected as one of the eight finalists for the indie game contest “Sense of Wonder Night 2026,” held as part of the Tokyo Game Show 2026. It was chosen from over 1,500 entries submitted from around the world for the indie game contest, with its originality highly praised.
The contest is a presentation event designed to discover game ideas that evoke a “sense of wonder”—those moments when “the world feels a little different the instant you see it or hear the concept.” It will be held on September 17, 2026, at the Makuhari Messe International Conference Hall, where the creators themselves will deliver their presentations.
*Legacy Code* is scheduled for release in 2027 for PC (Steam). The price has not yet been determined.
