Which computer game is properly the first video game: OXO (1952), Tennis for Two (1958), Spacewar! (1962), or a later commercially released title such as the Magnavox Odyssey games (1972)?

Historians disagree because the answer turns on a contested definition rather than a missing fact. OXO ran on a specific vacuum-tube computer for a single university event; Tennis for Two used an oscilloscope display built for a lab open house; Spacewar! was the first game widely copied among research institutions on a raster-style display; and the Magnavox Odyssey (1972) was the first to reach ordinary homes commercially. Each is a genuine first by a different, defensible definition of what counts as a video game, and no consensus definition has settled which definition governs the title.