Go to Endless mode, play up to and defeat Geese Howard. Once you beat him, go to any mode and highlight one of the indicated characters (on the left) and press R1 to access that hidden character (on the right).
|Kyo Kusanagi||Kyo Kusanagi (King 94 version)|
|Saishyu Kusanagi||Omega Rugal|
|Yashiro Nanakase||Yashiro Nanakase (Orochi version)|
|Shermie||Shermie (Orochi version)|
|Chris||Chris (Orochi version)|
Thanks to Revolution Readers Kimdan and horokusaki!