Guilty Gear XX Accent Core

To unlock the EX ending artwork, finish Arcade mode with the respective EX Character.

Hold down the corresponding button while highlighting Arcade Mode and press Circle.

Note: You can't use Gold or Shadow colors if you fight against Gold Characters.

To unlock the Guilty Gear Generations versions of the characters, play the game for a total of 48 hours.

GG Mode: Characters move faster, do relatively more damage, and can Instant Kill opponents without needing to charge. Bursts, Roman Cancels, and Faultless Defense are unavailable. Characters have the ability to charge their tension by holding the Heavy Slash and Dust buttons.

GGX Mode: Bursts and False Roman Cancels are unavailable. Characters can Faultless Defense Cancel their attacks.

After all the EX Characters have been unlocked, GGXX Slash Stages will slowly be Time Released in Hour increments. Once a stage is unlocked via Time Release, you have access not only to that Slash stage, but also the #Reload version of the stage.

To select the #Reload version of the stage, hold the "Respect" Button while selecting stages and Music, this is usually the R2 Button.

Play the game for more than 48 hours.

Do the following at the character selection screen.
This also works for EX characters, and possibly all GG modes. (GG GGX and AC)