Drive Meter
The mysterious "Drive" meter seems to tie-in to how many enemies you kill, and it may or may not be the only type. For example, it mentions that if you kill enough enemies, and the gauge fills to capacity, Sora is able to unleash a powerful attack (the meter keeps count). If you execute the attack enough, and kill enough enemies, the level of the meter increases, and the attacks/techniques Sora is able to utilize when the meter is full are upgraded (but you can still use the lower-level attacks by hitting the appropriate button when the gauge fills to that specific point). If you happen to defeat a boss with a "Drive"-based attack, you get double the "points" you'd get by just using it on a normal enemy.