The Nintendo World Event was held in Tokyo this weekend, and the 3DS was the highlight of the show. The videos embedded below obviously don't do the 3D elements of these games justice, but watching the videos does rather effectively show off how it will be implemented.
Starfox and Paper Mario look like just like their N64 inspirations, but with substantial graphical upgrades. Mario Kart, on the other hand, looks like an entirely new game.
Note: Videos for the additional games can be found after the jump.