Roxas deciding to fight the Organization by himself earns another one. These are the guys that give Sora trouble, and Roxas goes to fight them without anything more than two Keyblades.
Roxas: I am DONE WITH THIS.
The escape from the Castle That Never Was is pretty awesome too, in which a weakened Roxas takes down Saix, one of the stronger members of the Organization, who spent the whole game up to that point kicking Roxas and Xion, seemingly without breaking a sweat.
Beast's one-man-war against the heartless trying to invade his castle is mostly an Offscreen Moment of Awesome, but he does have one good moment partway through the game. After Roxas and Xion accomplish their objective of defeating a Neoshadow in Beast's Castle, two more pop up right behind them... which are promptly ripped to shreads in one shot each by The Beast flying in out of nowhere.