Natsume confirmed three Nintendo-related announcements for this E3. The community manager CeeCee wrote in a Tumblr update:
We’re saving a few secrets for closer to the show, but expect not one, not two, but THREE new Nintendo titles we’ll be announcing leading up to and at the show! This doesn’t include any classic eShop titles (and we’ll have some news on those as well). Will they be 3DS, Wii U, or a mix of the two, you ask? You’ll have to tune in from now until June 10th to find out!
