Galaxian (Namco set 2) could refer to a later release or a slightly revised version of Galaxian from the original developers, Namco. While the core gameplay would remain faithful to the original, small changes in graphics or other minor elements might differentiate it from the initial release. The specifics would require further information to identify what, if any, changes were made.

Galaxian (Namco set 2)

Galaxian (Midway set 1)