All three of these dates are different, which makes it hard to determine the actual build date. The Dev Menu date appears to be a Subversion timestamp, so that could be the date of the actual code; the XEX date would then be when the game was actually compiled. The disc label date is one day after the XEX, so that would be when it was actually burned to disc.
|Sonic games for the Xbox 360|
|Sonic the Hedgehog (2006) | Sonic Unleashed (2008) | Sonic's Ultimate Genesis Collection (2009) | Sonic & Sega All-Stars Racing (2010) | Sonic Free Riders (2010) | Sonic Generations (2011) | Sonic & All-Stars Racing Transformed (2012)|
|Pre-release Sonic games for Xbox 360|
|Sonic the Hedgehog (2006 Xbox Live Demo) | Sonic Unleashed (Xbox 360 Preview Build) | Sonic Generations (Demo 1/2)|