Jinpachi Mishima
     When   selecting  Jinpachi  pressing  [Square]  yields  his  Dark
Resurrection  fiery  demon form, [Triangle] grants you his human form,
and [Circle] and [X] will get you his original Tekken 5 demon form.

Jinpachi - Complete arcade mode

Unlockable Tekken 5 Stages
     Beat  the  arcade mode three times and the entire stage list from
Tekken 5 will be unlocked for use in versus play.

Tekken 5 Stages - Beat arcade mode 3 times

Unlockable Panda
     You have to select Kuma. The press [Circle].