As for RPG, you can get the two Etrian games. Etrian Odyssey IV and Etrian Odyssey Untold Millenium Girl you don't need to play the rest and Untold is a reimagine of the first game! Then you also have Shin Megami Tensei IV and if you missed it on the DS Devil Survivor Overclocked which is a "tactical RPG", also there is Soul Hackers but it's a bit too oldschool. There is also Fire Emblem Awakening, it's a strategy RPG and it's one of the best 3DS games!
Adventure games, well you have Ocarina of time and well... I don't know what is exactly an Adventure game but any Zelda is good.
As for platformers well... you have Super Mario 3D Land which is awesome and New Super Mario Bros 2, they are quite good!
"I've Underestimated the Horse Power from Mario Kart 8, I'll Never Doubt the WiiU's Engine Again"
