We also got confirmation of the board game-like Smash Tour mode, which was inadvertently revealed through an Amazon posting earlier this month.
The individual Smash fighters have a long gaming history, and you'll be able to demo some of their biggest titles within the Wii U version of Smash. While the presentation didn't specify how much game time you'd get with the classic games from Smash fighter's roster, the demos will link you to the Nintendo e-shop in case you want to buy them.
That leaked stage creator? That's in the game as well. You'll be able to craft stages for your friends to fight in by drawing original creations and filling them with items.
Mewtwo will be a downloadable fighter available if you buy both the 3DS and Wii U versions of Super Smash Bros. The character will be available for free on both systems, but its still in development and is scheduled for release sometime in Spring 2015.
The presentation is set to start at 3PM PST / 6PM ET.
Leaks have revealed that the game will have a stage creator and a "board game" mode, and we're expecting to hear something about that during the stream. But what do you most want to hear about? Let us know in the comments below!
We'll be updating this story with additional details as they're revealed.