You wanted surprises from Nintendo at E3. Here's one: The Legend of Zelda: Tri-Force Heroes, announced by Nintendo today at E3. It harkens back to Zelda co-op games like Four Swords Adventures, but this time for three players.
The 3DS game is played from an overhead perspective like classic Zelda games and is slated for a fall 2015 release. The core gameplay mechanic involves players stacking themselves into a sort of totem pole of heroes. The game also makes heavy use of costume switches, letting players dress their Links in costumes like the samurai armour or the "big bomb outfit" that grant special abilities.
The game is being overseen by long-time Zelda producer Eiji Aonuma and directed by Hiromasa Shikata, a long-time Zelda developer who most recently directed the 3DS' The Legend of Zelda: A Link Between Worlds and, if the online Nintendo fan-made wiki is correct, the three-player co-op Zelda attraction in the Wii U launch game Nintendo Land.
During a video presentation of the game, Aonuma and Shikata explained that the game is set in a kingdom obsessed with fashion and will have players gathering items to create special, empowering outfits. One appears to dress Link as... Zelda. The idea is that various people in this kingdom think they can dress up to save the day.
It's unclear how much of an overworld there will be, as the footage of the game focused on action taking place in dungeons. The totem mechanic got used a lot, with the top player on the stack tossing bombs into hard-to-reach areas, shooting targets and more. Enemies appeared to be designed to also make use of the verticality of the playing space. The designers said they want players to work together, emphasising co-op play as opposed to some of the competitive aspects of other multiplayer Zelda modes and games.
The game will have online mutliplayer, but for the multiplayer-phobic, don't fret. There will be a single-player mode that has the player switching between their own Link and two supporting "doll" characters.