Retro Mario RPG is an RPG for the Nintendo Wii and the Nintendo DSi. The DSi version is compatible with the DS, though it lacks the video input feature that is available for character customization.
One day while Mario was walking through mushroom way to Toad Town, a strange creature appears from the sky, turning everything 8-bit(except for the outline). Mario then rushes to Toad Town, and finds that everything there is also 8-bit. He also finds out that the creature is a bio-enginered soldier, that cannot distinguish between friend and foe, causing it to attempt to kill all life in the universe. Afterwards, at Princess Peach's castle, Princess Peach is kidnapped by the alien mercenary, Tatanga, and brought to Bowser's castle. Mario witnesses Tatanga flying away, and gives chase. Afterwards at Bowser's castle, Mario encounters a renegade Koopa Troopa battling other Koopa Troopas. The Koopa Troopa then notices Mario, and calls for help. Mario then joins in the battle. Afterwards, as thanks for helping him beat the other koopa troopas, the renegade Koopa Troopa, named Troop, joins Mario's party. To be continued...
- Mario: The famous plumber from the Mushroom Kingdom. Attacks with Punches, Kicks, Hammers, A Koopa Shell, Fireballs, and jumps.
- Troop: A renegade Koopa Troopa with customizable armor. Attacks with shells, capes, gusts of wind, spells, hammers, fireballs, boomerangs, and a Y-saber.
- Yoshi: The famous yoshi who saved Mario as a baby. Attacks with his toung, eggs, and ground pounds.
- Geno: Geno returns, and better than ever. He attacks with bullets, punches, and spells.
- Tatanga: The semifinal playable character. He uses laser beams, missiles, and dive bombing attacks.
- Ludwig von Koopa: After being sent into exile for being framed for killing Morton Koopa Jr., Ludwig joins Mario in his quest to restore the world to it's normal look. He attacks with flames, his shell, and musical notes. He has a bonus pallete after the world is returned to normal.