This game has been Greenlit by the Community!

The community has shown their interest in this game. Valve has reached out to this developer to start moving things toward release on Steam.

Retrobooster
Dev Story at Co-Optimus
August 15, 2013 - Really Slick

This article[www.co-optimus.com] is something I wrote for Co-Optimus about the co-op aspects of Retrobooster.