Unity was a shooter/music game by Jeff Minter (Llama Soft). It was cancelled, after approximately two years development, in December 2004. Unity was being made for the Nintendo Gamecube, and was gaining quite an interested following. The game would have seen release quite late in the system's life,
Unity was built concurrently with (or, it is perhaps more accurate to say, on top of) Minter's Virtual Light Machine (VLM) 3, which would be later developed further into the XBox 360's visualiser Neon. The VLM was used to create the environments, and enemy patterns based on the music.
It was hinted at, via the Llamasoft forums, that Aphex Twin were set to be doing the music for the game. Or, maybe it was Underworld
According to IGN's Unity page the game was to be released on '1 God', instead of the normal disc format. It was also to have Dualshock support.