Platform exclusive

See also: no ports (when there simply aren't any ports of the game to other platforms with no claims of platform exclusivity)

Commonly done by contract from the platform manufacturer/designer rather than because the publisher/developer wants it (as it reduces sales). Likely involves the platform manufacturer/designer contributing funding to the game development/advertisement in exchange. If the developer is not first party, then the exclusivity is likely timed exclusivity contract of 6 to 12 months.

The platform manufacturer/designer functioning as the publisher may cause this to happen as a matter of course (as often seen with Sony, Nintendo and Microsoft for example).