Gravity Swap 64 v1.0.3.1 is likely a homebrew game for the Nintendo 64, indicated by the version number. The game probably involves manipulating gravity or environments in some manner. Versioning suggests iterative development and updates by its creators. The actual gameplay mechanics are likely spread across dedicated online forums or communities that focus on fan-made Nintendo 64 games; however, the developer and publisher information is not currently available.

Gravity Swap 64 v1.0.3.1

Golden Nugget 64 (USA)