Retro Game Challenge Cheats

Rally King codes
Enter these codes at various points to unlock their effects.

[Select] [+] [Left] on title screen: Invincibility
Hold [Select], then press [Down] and [Right] on title screen: Make Rival Cars Disappear
[A] [B] [A] [B], then [Up] + [Select] on title screen: Start at Course 2
[A] [B] [A] [B], then [Left] + [Select] on title screen: Start at Course 3
[A] [B] [A] [B], then [Down] + [Select] on title screen: Start at Course 4

Star Prince codes
Enter these codes at various points to unlock their effects.

Hold [Left], press [Start] on Game Over screen: Continue from level you died on
Hold [Up] and press [A] [A] [A], then hold [Down] and press [B] [B] [B], on title screen: Invincibility

Warp to final level in Cosmic Gate
In the first stage, fire 64 shots without hitting any enemies. A warp gate will appear that will take you to the final stage.

Guadia Quest - "Beat" the game without beating the game
This trick will let you see the credits of Guadia Quest without having to go through the entire game, thus earning you the medal that recognizes your completion of the game (for Arino's final challenge). First go to the Mausoleum (the path to get to the Mausoleum is located east of Centraan between some mountains and the ocean; you will need to enter the path from north of the mountains). After you go into the Mausoleum, walk nine steps up (you will be in the top left corner). Then press "A" to open the menu and select "Look."

Cosmic Gate Special Stages
A set of special stages can be accessed by playing on hard mode and activating the warp gate in stage 64. Activating the gate will take you from stage 64 to stage EE which continues through all of these stages: EF, F0, F1, F2, F3, F4, F5, F6, F7, F8, F9, FA, FB, FC, FD, FE, FF, and finally 00 which upon completion will loop you back to stage 1 again.