Metroid Database.com

In this Smash Bros. Direct a lot of information was revealed especially for the Metroid series. First off as seen above Zero Suit Samus returns as a playable fighter. In this game Zamus is stand alone character who does not transform during battle. She has also been given a fancy new pair of rocket boots to increase her recovery.

Some news relating to Ridley and Dark Samus has also been revealed. Ridley will be appearing in Smash as a boss character once again. Not much was seen except for a shadow and part of his tail on the Pyrosphere stage. Dark Samus will also appear as a third Metroid themed Assist Trophy, joining the ranks of Mother Brain and Metroid. The King Kihunter from Other M appears as a trophy, with regular Kihunters appearing as enemies in the single player mode Smash Run on 3DS.

Smash Bros. for 3DS will be released this summer following by the Wii U version this winter.

EDIT

Courtesy of NeoGAF we have a much larger image of the Zero Suit artwork. And yes, Samus retains her beauty mark.

--James Pierce