Gamma 64 is a homebrew game for the Nintendo 64. Its development likely began as a personal project, testing the boundaries of the N64's capabilities. Gameplay would vary depending on the specific version, focusing on demonstrating programming techniques or showcasing certain graphical capabilities of the console.  The developers are likely individual hobbyist programmers within the homebrew community. 

Gamma 64 Demo v0.92

Gadget The Wolf 64 Playable