Cheats for Ridge Racer DS (DS)
To play on a reverse track, drive forward at the starting point until you get to fifth gear. Then, make a "U" turn and drive towards the wall. If done correctly, you will hit sixth gear and the wall will disappear. The track will now be in reverse.
Play ten multi-player races using a single cartridge to unlock the 00-Agent car. Keep playing in multi-player mode to continue unlocking bonus cars, in the following order: Red Shirt Rage, Pooka, Caddy Car, Galaga '88, Shy Guy, and Mario Racing. Win all the Platinum GP races to unlock all bonus cars in the game.