TEKKEN TAG TOURNAMENT UNLOCKABLES
Fight as Heihachi
Finish the game under the normal difficulty setting (for at least two rounds) without losing any rounds, in less than 5 minutes, 30 seconds.
Fight as Tiger
Push Start at Eddy's highlight screen.
Fight as Tetsujin and Unknown in arcade mode
After you have unlocked these two characters, choose arcade mode, and scroll down the character list to the bottom left corner (Wang). Push Left and will this option will appear.
Special costumes
When choosing Jun, Michelle, Ganryu, Forest, Jin, Xiaoyu, Kunimitsu, Lee, Devil, or Eddy push Start.