Among the changes included: velocity sensitivity for Ion Drum Kits, "much more robust handling of chord hammer-ons and pull-offs," a "Sort by Stars" option in Quickplay, and support for the user-created songs eventually coming to PS3 via Rock Band Network.
While the Rock Band Network and its wealth of user-made content are based on Xbox 360 due to RBN's use of Microsoft's XNA Creators Club platform, Harmonix has vowed that select "stand out tracks" will be eventually be sold on PlayStation 3 and Wii.
Come January 7 RB2 PS3 will be prompted to download the free update booting the music game whilst connected to the PlayStation Network, with the notes below:
"Sort by Stars" in Quickplay. If you hit the "Sort" button on the Song Select screen, you'll come to a brand new sort that orders songs by the star ratings that you've achieved on each song. Each star rating gets a category, as well as an "Unplayed" category for songs that don't have a star rating recorded. Finally, you can record your progress towards gold starring every song in your library! Improved "Sort by Stars" fix: Players will not have to beat a previous high score to record a star rating for their songs. Chord HOPO improvements: If you've played The Beatles: Rock Band, you'll notice much more robust handling of chord hammer-ons and pull-offs. This patch implements those changes in Rock Band 2 to provide a more natural chord hammer-on/pull-off experience. Velocity Sensitivity on Ion Drum Kits: Ion Drum kits now support velocity sensitivity in both drum fills and Drum Freestyle mode. Rock Band Network Store Support: When the Rock Band Network goes live, select songs will be available for PlayStation 3 users through a new storefront available in game. Stay tuned for more information closer to the launch of RBN! SingStar Wireless Microphone Support. Rock Band 2 now supports the SingStar Wireless Microphones currently available through Europe! Finally, you can now have a fully wireless Rock Band experience on your PlayStation 3!