Yume Koujou: Doki Doki Panic

Yume Koujou: Doki Doki Panic
Developer: Nintendo Publisher: Fuji Television Platform: Famicom Disk System Released in JP: July 10, 1987 This game has unused graphics. This game has anti-piracy features. This game has a prerelease article

Dream Factory: Heart-Pounding Panic is a side-scrolling platformer developed in collaboration with Japanese TV network Fuji TV in order to help promote their 1987 Yume Koujou (Dream Factory) event. The game revolves around an Arabian family (Mama, Papa, Imajin, and Lina) venturing into the storybook land of Muu in order to rescue the family's two youngest children from the evil Mamu.

It is better known in the west as the game that served as the basis for the international version of Super Mario Bros. 2, with many of its original elements and characters ending up being incorporated into the Mario canon through their inclusion in subsequent games. Doki Doki Panic itself, however, has never been rereleased (likely owing to rights issues, with Fuji TV owning "Yume Koujou" and the characters that were ousted for Super Mario Bros. 2), with very few mentions of it in other Nintendo titles.

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Prerelease Info

Unused Graphics

Present in the tileset for the desert stages is a little smiley face, possibly just a placeholder. It's still present in the prototype and final versions of Super Mario Bros. 2, but remains unused. Super Mario All-Stars, BS Super Mario USA, and Super Mario Advance don't have this graphic at all.

Anti-Piracy

Original/authorized copies of Doki Doki Panic have the file count for Side B in the disk header intentionally set to 13, rather than 14 (the actual number of files on the disk). Unauthorized disk-copying tools originally relied on this value to know how many files to copy to the new disk, and as a result would end up skipping the very last file, appropriately named DUMMY-DT. The game uses a specific BIOS call to search for this file's ID number ($C0, or 192) when loading data from Side B, and if it is not present the screen shown to the left is displayed.

Interestingly, DUMMY-DT is loaded into RAM at $6600, though it contains nothing more than an empty save file and two signature bytes (00 00 00 00 5A A5). The real save file from Side A has already been loaded into RAM and copied to an alternate location by the time this file is loaded, so its actual contents don't matter.

To see this screen, remove DUMMY-DT from Side B or set the PC to $66A2 before entering a level.

(Source: Rusty, http://www.famicomdisksystem.com/disk-copy)