According to TSSZ News:
"Originally, the Steam PC version of Sonic & All-Stars Racing Transformed was scheduled to unlock for those pre-ordering at 1PM Eastern time this afternoon. But it appears the download unlocked a bit earlier than expected today.
The PC port contains several added characters, including the main cast of Team Fortress 2, the manager from the Football Manager series, the Shogun from the Total War series.
A few problems have been reported with the PC edition, including problems accessing the game's configuration menu, and trouble scaling the video resolution beyond 720p."
Is Like Mario Kart 7