The most interesting bonus feature is the ability to download a save file to your VMU which unlocks everything in the game.
You can also watch a Japanese TV commercial (with English subs).
Furthermore, @ItsFantasticAC has contributed translated interviews from the game's Japanese guide, which was released in 2001 but never made it out of Japan.
The content is tucked away in the game's main menu, in the spot that would normally be occupied by the now-dead "Network Mode".
This is shaping up to be a pretty significant patch, and one I personally cannot wait to get my hands on.
Capcom Vs SNK 2 Is Getting Cool Bonus Content On Dreamcast Thanks To A Fan-Made Upgrade
Gain some insight from the original developers
www.timeextension.com