Publisher: Vidco

Vidco was a small American company connected with unreleased Atari 2600 games from 1983. Its prototypes surfaced together with those of Zimag, and the two names are hard to separate. The site lists two games under Vidco. A Mysterious Thief is a burglary game against the clock, preserved here as a one-of-a-kind NTSC prototype and now thought to be an American game by Zimag or Vidco. Immies & Aggies is a rough marble-shooting prototype that Zimag’s catalogue listed for spring 1983. Both games were later sold elsewhere under other names.
Try both prototypes below in your browser.