Most of the reveals are item-based: you may now move freely with projectile weapons (finally!), and as detailed earlier here, the new "Gooey Bomb" item was unveiled. The most interesting new item, however, is the Smash Ball, which activates character-specific "Final Smash" attacks. Mario's is entitled the "Mario Finale" attack, which unleashes a spread-fire explosion attack, and we've seen Link's Triforce blade attack in an earlier video. Since most competitive Smash Bros. players contend without the randomizing effect of items, it'll be interesting to see if this affects higher-level gameplay.
Also unveiled are some of Pit's (of Kid Icarus fame) attacks, which include a controllable arrow of light and limited flight capabilities (most likely the Up+B special). Brawl looks like it's coming together nicely ... do you guys agree?