This version, again like Gold and Silver, supports wireless trading and battling, as well as the Time Capsule option that allows Pokemon from Red, Blue and Yellow (all also available on Virtual Console) to be traded and battled.
In Japan (per Serebii), Crystal will receive a boxed release featuring a code for the game, a Game Boy cartridge-styled magnet, stickers and a poster. Gold and Silver also received this treatment in Europe, although we've had no word of the same for Crystal in the west.
Way back in 2001, we awarded Pokemon Crystal a 9/10 review, calling it "one last hurrah for the Pocket Monsters on the Game Boy Color", but criticising its relatively small difference from Gold and Silver. Joe Skrebels is IGN's UK News Editor, and Crystal was the first Pokemon game he didn't own. Follow him on Twitter.