The demo that Gamespot played allowed them to pick from four characters: Warrior of Light, Tidus, Onion Knight, and Garland. As you'd expect, each of them fights in different styles. For instance, Tidus from FFX is a well-rounded fighter who uses his sword and also fights with blitzballs; in fact, one of his moves is the Jecht shot. Garland, an armored antagonist from FFI, is bigger and more of a heavy-weighted fighter who's slow but powerful. The Onion Knight from FFIII may look dinky compared to the other fighters, but looks can be deceiving. Aside of being able to use magic, his sword attack hits multiple times in a brief second, very much like it did in FFIII.
The game only uses two buttons for attacking, which Gamespot will explain later, but you can perform different kinds of attacks by holding onto a direction when you press an attack button. The attacks also change depending on whether you're in the air or on the ground. Gamespot is told that you can gain new moves as you progress through the game and power up.