To Access hidden characters:

SNK characters:
- On the player select screen hold down the J key (LB on controller)on the right column of SNK characters (The column featuring Kyo) then push up or down to feature the hidden characters - Geese, Mars People, Goenitz, Iori, Mr. Karate, Athena.

Capcom characters:
- On the player select hold down the J key (LB on Controller) on the left column of Capcom Characters) The Column featuring Ryu) then push up or down to feature the hidden characters - Zero, Dimitri, Dan, Violent Ken, Shin-Akuma, Red Arremer

Notes: The version of Zero is from the Mega Man Zero series on GBA.