What's your favorite game you never hear anybody talk about?
Mine has to be Dragon Quest: Rocket Slime, a DS spin off of the Dragon Quest series that sees you playing as a slime operating a tank and rescuing the people from your town. You run around the overworld, collecting items to use as ammunition and saving money to upgrade your tank. The art and music are just as great as you'd expect from the Dragon Quest series. It made fantastic use of the DS's dual screens. It's also written for a younger audience, so a lot of it is just really silly and fun! Try it out for sure, I'm so sad there's no sequel :(
Loco-Roco for the PSP. As a game developer, I consider this to be the pinnacle of game development. It is completely original, uses only two buttons, super intuitive, yet your drawn into it and want to play for hours. It makes me sad that few have heard of it.
Toy Story on the sega genesis (and snes) is a close second. It is actually a bit of a hot mess, each level is a completely different style of gameplay. But it is super rewarding to fight your way through to the end. And it showcases so many different styles of gameplay.