TerraTech Legion is a spin-off of the TerraTech series that turns its modular vehicle building into roguelite horde-survival action. Players build and upgrade a combat vehicle from interchangeable blocks during each run while fending off ever-growing waves of enemies.

It keeps the series' creative block-based construction at its core while framing it around fast, replayable runs, appealing to fans of both construction sandboxes and survivor-style action games.