with all you've gotIn the awesome pixelated game that is Kingdom Hearts: Chain of Memories, there exists a part in which you can play as Riku. In battle, he can go into Dark Mode to use his dark powers. Certain combos can be performed during this time:
Dark Break - Jump up and slash downwards 5 times.
Dark Firaga - Homing fireball.
Dark Aura - Teleport around & attack, followed by explosions. Yes folks, this is the same attack he used on Sora in Kingdom Hearts.
Last but certainly not the least, Riku can call upon the help of his good friend the King to perform:
MM Miracle - Restores HP & stuns/damages all enemies