TIS-100 is a 2015 puzzle video game developed by Zachtronics Industries. The game has the player develop mock assembly language code to perform certain tasks on a virtualized 1980 computer that has been corrupted. The game was released for Microsoft Windows on the Steam's Early access program on June 1, 2015, and OS X and Linux versions followed a few days later. A final release followed on July 20, 2015.