Are there any glitches in Kingdom Hearts 2?

Answer 1

Yes, actually, there are two to my knowledge, both pertaining to the Driver Gauge.

-At the start of The World That Never Was, in Alley to Between, if you call a Summon and then walk through the portal into Betwixt and Between, your Driver Gauge will be automatically refilled. This is also a very good way to boost the levels on Sora's Valor form. In the area after Alley to Between, there are unlimited Heartless wandering about. You can use Valor and just keep knocking them down as they come, then go back, call a Summon, go through the portal, and get your Guage refilled. Marvelous, isn't it?

-The second is similar. At any save point in the game where you can access the World Map, if you leave for the map while in one of Sora's different Forms, and then return to that same world, your Driver Gauge will be completely restored.

They may not be "cheat codes," but believe me, they really do help.