Nintendo has confirmed that Splatoon will be releasing on May 29, 2015.  During the Nintendo Direct, several modes were showcased including Ranked Battles and the Battle Dojo.  Ranked Battles feature a ranking system (naturally) and would be similar to Super Smash Bros.’ “For Glory” mode.  The Battle Dojo is a new mode that allows 2 players, one using the Wii U GamePad and one using the TV, to hone their skills.  There are balloons throughout the levels so it’s mostly a target practice mode where players can develop skills and strategies.

Splatoon amiibo are also coming soon.  Nintendo confirmed a boy inkling, a girl inkling, and a squid amiibo.  Players can choose to pick up all 3 in a set or purchase the boy or girl inkling separately.  The amiibo can also unlock special missions and unlock various outfits in the game.

Source: Nintendo Direct