This version features 720p resolution, enhanced draw distance, and Achievement support. Find the full list of Achievements here.
This version replaces the Xbox Originals version of Grand Theft Auto: San Andreas, which has been removed from the Xbox Live Marketplace. If you purchased the Xbox Originals version, you’ll still be able to download it via your download history, but you’ll have the option to purchase the new version, as well.
As for why this updated Grand Theft Auto: San Andreas remains an Xbox 360-only ordeal, we’ve reached out to Rockstar Games but have not yet heard back.