Outside of Nintendo's first party offerings, most of the Wii U titles on showcase at Nintendo's E3 press conference were western titles like Mass Effect 3, Assassins Creed III, ZombiU and Rayman Legends. There were a few exceptions from Namco Bandai and Tecmo Koei, though. Look below for screens and media of Tekken Tag Tournament 2, Ninja Gaiden 3 Razor's Edge (released outside of Japan by Nintendo) and the newly announced Tank! Tank! Tank!
For screens of the full Wii U first and third party lineup, see Nintendo's E3 portal page.
Tank! Tank! Tank!
Tank! Tank! Tank originates as a Namco Bandai arcade game. See our impressions of the arcade version from way back in 2009 here.
Tekken Tag Tournament 2
Yes, just the one screenshot. See the Wii U lineup reel for a brief look at what the mushroom does.
Ninja Gaiden 3 Razor's Edge