Sonic and Sega All-Stars Racing has gotten a major update adding new content and several cool new technical features.
Two new racers have been added. Knuckles and Shadow from the Sonic series can be unlocked, though they don't come cheap, at 500,000 and 750,000 "Sega Miles" (in-game currency) each, though 1.5 million Sega Miles go for $1.99. Inflation has hit Green Hill hard, apprently. As well, there's a new Samba de Amigo-inspired course, Sun Fair.
On the technical side of things, the universal app has been updated with HDMI and AirPlay Mirroring support, meaning the game can be played in full widescreen HD on an HDTV. The update also claims to add in iCloud progress synchronization to the universal app, but I was not able to get it working in testing. This may be in part due to some issues with OpenFeint, but iCloud support has frequently been an issue for games. As well, it's now possible to see friends' Game Center profile avatars when racing online, in order to see just who needs to be passed up. The update is available now.