Knockout

Knockout was designed by D. Gottlieb & Company (then a Columbia Pictures Industries company) but was never put into production. It was reportedly intended as a 1-player solid-state version of Gottlieb's 1979 'T.K.O.' for the Italian market, but the project was shelved because T.K.O. itself was not well received. A single full prototype was reportedly located in England in 2011, making it an extraordinarily rare piece rather than a machine that collectors can realistically obtain.

As planned, gameplay would have centered on the theme of professional boxing, with artwork by Gordon Morison. In the upper right corner of the backglass are five orange circles meant to represent arena floodlights — a detail not found on T.K.O. — which are believed to have disguised extra-ball lamps in a style typical of Italian games. According to Federico Croci, a collector in Italy, this would have made Knockout the only solid-state game with extra-ball management similar to Italian EM games, had it been produced.

Because it never reached production, little else is documented about Knockout. Its status as an unreleased prototype, rather than a manufactured pinball machine, makes it a significant curiosity in Gottlieb's history rather than a conventional collectible.