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 :(
Soul Bubbles is a puzzle-action game released for the NDS. You encase the souls of the departed in magic bubbles and blow them around levels to help them to the afterlife, dodging spiky terrain, marauding creatures, and wind currents.
It might have gotten more attention if its production run wasn’t so small and it wasn’t sold exclusively at Toys 'R Us.