I think there's a lot being looked over too if your'e a nintendo fan. Box boy came out this year and that didn't disappoint in the slightest in it's minimalistic way~! wonderful Indie stuff all made some bretty big splashes on Wii U, even if some of that was rereleases like Plague of Shadows and Freedom Planet. I'd also take a shot in the dark and say that one of the most acclaimed indie games on PC this year is very much a certain flavor of game for a certain flavor of Nintendo fan.
also, I think its telling that I effectively doubled my Wii U retail library in 2015. (I had Nintendoland, New Super Mario U+ Luigi U, 3D world, Smash 4, Mario Kart 8, Pikmin 3 before, aquired Kirby and the Rainbow Curse Mario Party 10 (Gift, played it once), splatoon, Super Mario Maker, Yoshi's Wooly World, Xenoblade Chronicles X)
... Still need to get Bayo 2.