Guilty Gear XX Accent Core

Characters (EX):
To get the EX Characters, beat the Shadow version of them in Survival mode. To select them, hit Start on the select screen.

Ending Artwork (EX):
To get the EX ending artwork, complete Arcade mode with the corresponding EX Character.

Battle EX characters in Arcade mode:
Select the "Arcade mode" option, then hold L2 and hit Circle.

Battle Gold characters in Arcade mode:
Select the "Arcade mode" option; next, hold L1 and hit Circle.