Developer: On-Line Systems

On-Line Systems was the computer game publisher co-founded by Ken Williams and later known as Sierra On-Line. It did not publish Atari 2600 cartridges itself. Tigervision licensed three of its computer games and brought them to the console in 1982, and those versions are credited to On-Line Systems here.

Threshold: a conversion of Warren Schwader’s 1981 Apple II shooter, with 11 kinds of alien wave and, unusually, free movement up and down.
Marauder: break into a robot-guarded base and destroy its power center. The 2600 version was programmed by Rorke Weigandt.
Jawbreaker: John Harris’s candy-factory maze game, rebuilt for the 2600 around rows of candy and sliding doors.

Jawbreaker’s computer original looked enough like Pac-Man that Atari tried, without success, to stop it in court. All three play well on the keyboard, so choose one below and start it in your browser.