So, you wanna know how to unlock everything in Evil Zone? Most of them aren't too difficult, don't worry:
The Gallery - To unlock the Gallery (and the Extra options in general), complete Story Mode with any character.
You could just use this Gameshark Code and unlock everything:
But where's the fun in that?
Super Moves and Death Moves
In the game, when you have stocked a jewel (by holding down the attack button until your life bar fills up), you can use it to deliver powerful attacks that can turn the tide in battle.
Most of you probably actually already know about the Death Moves, which are used with Back-Back-Attack; it sends out a projectile that, if it is not blocked or dodged, will deliver your character's ultra attack (and an even more ultra attack if the damage will kill your opponent). However, what isn't pointed out in the instructions or many FAQs is that jewels can also be used to supercharge one or occasionally two of your character's ordinary moves by doing the usual motion for the move and holding down the attack button (instead of tapping it once or twice). You'll know you've succeeded if the character charges up their energy for a moment before striking with the enhanced attack.
Keiya Is Da Man
Keiya has a unique ability that no other character seems to share, namely the ability to instantly charge a jewel. Simply use Back+Attack+Attack (the red pentacle attack). If it successfully hits, Keiya will receive a jewel.