Super Smash Bros. Nintendo Direct Summary

If you missed the recent Nintendo Direct that served as a special showcase the upcoming Super Smash Bros. then don't panic, we've got your back with a brief summary:

The 3DS version will launch in Summer, and the Wii U version will launch in Winter. But both are expected this year.
The 3DS version will run at 60fps even with 3D turned on. However Assist trophies and some Pokemon will run in 30fps.
The 3DS version will have an exclusive mode - "Smash Run" - where players explore a dungeon picking up power ups, then battle against each other once all the power ups have been applied.
As we already knew, the character roster will be the same between the two versions but there will be different stages. The 3DS version will focus on portable game stages, and the Wii U focuses on stages from console games.
The 3DS version will have two musical pieces per stage, while the Wii U version will allow several different tunes to play.
Dr. Wily’s Castle from Mega Man 2 will be a new stage.
Some stages, like Dr. Wily’s Castle, will feature stage-specific bosses like the Yellow Devil, which will explode when defeated and fire across the screen, meaning players can use it tactically to cause an explosion.
Rare pokemon will now come in a master ball, not a standard pokeball.

Here are some important changes to characters to take note of:

Characters that would have different forms no longer change,. Instead these have been added as different characters (e.g. there's both Sheik and Zero Suit Samus)
Zero Suit Samus now has jet boots, that look like they've been stolen from Bayonetta.
Zelda uses a new attack called Phantom Slash which calls a big guardian to attack for her or defend her.
Sheik now has Burst Grenades and "Bouncing Fish", which sadly isn't a fish, but is instead a heel kick.
Lucario's Aura Attacks have been buffed and he can now perform a Mega Evolution.
Charizard can also perform a Mega Evolution.
Olimar can now only have up to three Pikmin follow at once, but they can be red, yellow, blue, white and/or purple.
Pit's gliding mechanic has been replaced with the Power of Flight which basically shoots him across the screen.
Rosalina can keep her Luma with her or shoot him out with a Luma Shot. When he's on his own he'll roam the stage and fight.
Mega Man has moves from previous games: The Slide, Charge shot, Uppercut, Flame Sword, Flame Blast, Leaf Shield, and lots more. For his Final Smash a bunch of his counterparts from games like Mega Man X come on stage and shoot a massive energy blast.
Little Mac has a power meter which fills up when he takes damage. When it's full, Mac can pull off a one-hit KO. His final smash changes him into Giga Mac. He's a powerhouse on the ground, but when he's in the air he's pretty much useless. Oh and he's got no recovery if he falls off stage.

Online Play:

Both modes will have online play
You can play with friends or strangers
There are two modes:

For Fun - This mode is what you'd expect; a non-competitive version of the game. This mode allows you to play any stage without going into its Final Destination mode (it's basically a cut down version of the map that doesn't have any layers or platforms).

For Glory - This mode is the ranked version; there are no items, your wins and losses are counted, and all maps are in their "Final Destination" mode.

You'll have a name linked to your Nintendo ID
There'll be a code of conduct in place with bans for people who are basically trolling; the worse you behave the longer your ban.
In place of a traditional ranking system players will have a Global Smash Power.

And finally, the really important bit, the new guys! You may have noticed the headline image. If you couldn't work it out then we'll list the two characters that were revealed below:

Charizard
Greninja