Full list of info for those who missed the direct.
3DS version of Smash Bros due Summer 2014, Wii U version due Winter 2014.
3DS version will run at 60fps. No confirmed fps for the Wii U version.
Both games will have the same characters, but different stages.
Various stages were shown. Notable new stages include Balloon Fight (a stage nearly identical to Balloon Fighter) for the 3DS version and Patulena's Temple (a large Hyrule Castle-esque stage) for the Wii U version.
Stages from previous games will also return, such as Jungle Japes. Final Destination is also confirmed and looks absolutely fucking gorgeous.
The Wily's Castle stage has the Yellow Devil as a stage hazard. He can be hurt by attacking his eye; the fighter to deal the killing blow will cause the Yellow Devil to explode with huge damage, hurting enemy fighters within the blast.
Ridley confirmed... as a stage hazard. Finally, everyone can shut the fuck up about him.
Online with Anyone returns with two modes; Play for Fun (random stage, all items, only counts wins) and Play for Glory (Final Destination, no items, counts wins and losses)
Various stages also have a "Final Destination" mode which removes all platforms and stage hazards.
Scoring system for solo players announced, called Smash Global Power - essentially gives you a number of how many players you are better than (or worse than - admittedly, this was presented pretty vaguely.)
No online rankings, but matchmaking will be skill-based (especially for Play for Glory.)
Several new items announced, including the Rocket Belt (a jetpack that lets you hover for a short time, ala Cave Story's Booster) and the Bombchu (the Zelda bomb that crawls along surfaces.)
Master Ball is another new item. Works like a Pokeball, but only has rare or legendary Pokemon. Some new Pokemon include Fennekin, Gogoat, and Kyurem.
Zero Suit Samus is not returning to the franchise JUST KIDDING returning, along with Sheik. These characters are now separate from their original characters; they are now individual characters, and their form changing mechanics are either removed or replaced.
Lucario's aura works as before. Lucario can also Mega Evolve, giving him maximum aura no matter how much damage he has taken. How Lucario Mega Evolves is unknown (though the current bet is it is his new Final Smash.)
Olimar can now have up to three Pikmin at once. Olimar's recovery move is now Winged Pikmin, which is very good. However, the more Pikmin he has, the heavier he becomes and the worse the recovery becomes as a result.
Megaman's Final Smash is calling all of his counterparts (Megaman X, Megaman Legends, Megaman Zero, etc.) and combining all their fully charged Busters into your face. Fangasms ensued.
Pit is stronger than he was before, but can no longer glide. His Final Smash is now no longer broken The Three Treasures (or something) which is basically him going crazy with his bow, shooting huge arrows or arrows falling from the sky and lots of flashy lasers.
Yoshi confirmed. He walks upright now. Aaaand that's about it, any other changes were left unmentioned.
Mac deals lots of damage when on the ground, but becomes significantly weaker in the air. His power meter builds by both dealing and taking damage; when full, he can unleash a one-hit-KO attack (if it lands, of course.)
Custom move sets are a feature now. These are only available in offline play or online matches with friends; online matches with anyone are restricted to the character's normal move set. A few previews included Mario's fireball travelling slower but being a larger projectile, or DK's headbutt being replaced with a much slower but super-armored wind-up punch. More information on this "coming soon."
3DS version has a unique multiplayer gamemode called Smash Run. To sum it up quickly, it's the City Trial thing from Kirby's Air Ride; fight enemies and gain powerups for five minutes, then fight each other at the end of the time limit with those powerups.
Finally, Charizard confirmed as a standalone fighter (along with his Mega Evolution, also unknown how this occurs but probably his Final Smash) and Greninja confirmed right the fuck out of nowhere. Mewtwo players continue to cry.
While the Pokemon confirmations have pretty much put a nail in Mewtwo's coffin and straight through my heart (seriously, he's my favorite character in Project M at the moment) Greninja looks really fun to play.