A game demo is a trial version of a video game that is limited to a certain time period or a point in progress. A game demo comes in forms such as shareware, demo disc, downloadable software, and tech demos.

id Software LLC is an American video game developer based in Richardson, Texas. It was founded on February 1, 1991, by four members of the computer company Softdisk: programmers John Carmack and John Romero, game designer Tom Hall, and artist Adrian Carmack.