To claim the steam key just scroll down and enter your email address, you should receive an email within 60 minutes.
Blurb from Steam:
Racer 8 is the ultimate Rally inspired puzzle game that will have players revving their engines or leave them running on fumes!
A mixture of asset management, time trial and puzzle game, Racer 8 plays on several different mechanics to keep players’ heads constantly spinning.
Navigate your car, which is constantly in motion while rotate the square tiles on the map grid in order to form a track for your car to follow, through a series of checkpoints and ultimately across the finish line.
http://store.steampowered.com/app/292380