Astro Chase

Astro Chase was advertised by First Star Software as a future title for the Atari 2600, but they only ended up releasing Boing! before giving up on the Atari 2600 market. While Parker Brothers had the rights to the cartridge versions for the Atari 400, Atari 800 and Atari 5200 versions, First Star appears to have been planning on releasing this one themselves (they also released the disk and tape versions for the Atari Home Computers and Commodore 64), but eventually sold the rights to Parker Brothers who never released it, most likely due to the crowded and collapsing VCS game market. A second (mid level WIP) prototype of this game surfaced in a Parker Brothers cartridge and came from a former Parker Brothers employee.

It's possible that the second cart shown below contains the PAL version.