STAGE ENTRIES
All veterans have the same stage entries as before.
Greninja appears out of a Poké Ball thrown onstage.
Wii Fit Trainer is already on the battlefield, as she wraps up her Tree pose, stepping off of her living Wii Balance Board.
Rosalina descends down on to the stage really fast in a spiral motion.
Villager's house appears out of thin air, followed by him/her skipping out the door, waving to the camera.
VICTORY POSES
Wii Fit Trainer does a Tree pose, followed by a Warrior pose, and says "You need to control your balance!".
Villager catches a beetle with his net, and shows it off.
Little Mac's victory poses feature Doc Louis.
VICTORY THEMES
From what I was able to hear, Mega Man's appears to be a boss clear theme from one of the NES games.
Bowser has a rock remix of the usual Mario victory theme.
Rosalina has the intro to Super Mario Galaxy.
Wii Fit Trainer's theme is a more celebratory version of the 10-note melody that is somewhat the "main theme" of the Wii Fit series, heard on many occasions across the 3 games.
Little Mac's theme comes from the original Punch-Out!! on the NES, after you win a fight.
STAGE MUSIC
The music that plays during Smash Run depends on the character you use.
Town & City has a medley of The City, the main theme of Wild World and City Folk, and 2:00 AM.
Reset Bomb Forest has Chapter 11: Viridi, the Goddess of Nature.
Ghiriham's Theme is mixed in with the Ballad of the Goddess on Skyloft.
The main theme for this new Smash game plays on Battlefield.
GAMEPLAY
When rolling , you'll stay in the same direction as before.
Pikachu's Quick Attack can now move three times.
Fox's Illusion doesn't leave him in free fall after use.
VOICE ACTING
Fox has a new voice actor.
Kerri Kane appears to be reprising her role from Mario Kart 7 as Rosalina.
Makiko Ohmoto expectedly returns to voice Kirby, and she's even recorded entirely new voice samples!
October Moore reprises her role for the female Wii Fit Trainer.
The Villager has a voice, too, it seems. We hear the female one saying "Thanks, Nook!" after handing him the Bells during Dream Home.
Antony Del Rios's back for Pit after Uprising.
ASSIST TROPHIES
Shadow
Starfy
Magnus
Chunky Kong
POKÉMON
Giratina's new, and uses some sort of wind move.
Victini does...nothing?
SMASH RUN ENEMIES
Egg-Robo (Sonic the Hedgehog)
Yellow Ghost (Find Mii) (It's also worth noting that they can protect themselves with colored shields, but whether they have special immunity like in the original games is unknown.)
Bubbles (The Legend of Zelda)
OTHER
The Wii U GamePad can be used for Off-TV Play.
We finally heard the new announcer!