| Super Mario Bros. 2 shrinks a character whose life meter is down to one mark. Chris Kohler's report on Kensuke Tanabe's talk says it was added because growing and shrinking was one of Mario's best-known traits. SMB2's cartridge keeps a full-size and a small tile bank for each character; Doki Doki Panic's disk has one tile file for each of its four, IMAJIN-C, LINA-C, MAMA-C, and PAPA-C, of 832 bytes. | closing paragraphs | Interview |
| Doki Doki Panic's final boss, Mamu, is Super Mario Bros. 2's Wart; each manual names its own. Kensuke Tanabe's team added enemy characters and visual nods to the Mario games for the American release, Chris Kohler reported. | closing paragraphs | Manual |
| Super Mario Bros. 2's song data shares no run of more than 5 bytes with either Doki Doki Panic disk: that is the longest run found for the twelve data regions of the ROM map's music part (the songs, their pointers and headers, and the level music indexes). The sound engine's six regions share none of more than 17 bytes and the sound effects' three none of more than 14, while the two routines that pick an area's music share a run of 24 bytes. Tanabe's team greatly enhanced the sound effects, Chris Kohler reported. | closing paragraphs | Interview |
| Nintendo brought the game to the Famicom in Japan on 14 September 1992 as Super Mario USA. Famicom Tsūshin's review gives the date and calls it the NES version of Mario 2, built on the disk game Doki Doki Panic, landing in Japan again. | last paragraph | Magazine |
| Chris Kohler reported, from an interview with Kensuke Tanabe, that Doki Doki Panic was a tie-in that Nintendo made under a deal with Fuji Television for its Yume Kōjō ("Dream Factory") expo, starring the expo's mascots. Tanabe recalled being handed a sheet of characters at Fuji Television and told to make a game with them. | Doki Doki Panic sectionDoki Doki Panic sectionDoki Doki Panic section | Interview |
| Tanabe told Kohler the game grew out of a prototype that SRD programmed for Nintendo: a two-player game that scrolled up as the players climbed, stacking blocks and throwing each other. Shigeru Miyamoto suggested making it scroll sideways and more like Mario. Tanabe said picking up blocks became pulling vegetables from the ground, and throwing the other player became throwing enemies. | opening paragraphsopening paragraphsafter the Miyamoto quotebefore the Fuji dealbefore the Fuji deal | Interview |
| Kensuke Tanabe directed the game. He said in 2004 that it was the first game he directed, and Kohler's 2011 report calls him its director. Kohler writes that Doki Doki Panic was made by the Mario team. | opening paragraphafter "You may already know the rest of the story" | Interview |
| Retellings agree that Nintendo didn't release the Japanese Super Mario Bros. 2 in North America and remade Doki Doki Panic as the sequel instead. IGN's 2010 history says Nintendo judged the Japanese game too hard for North American players and cancelled its release there, and Boss Fight Books' description of Jon Irwin's book says Nintendo of America declared it "too hard". | "You may already know the rest of the story" | Web |
| Tanabe told Kohler that moving the disk game to a cartridge for America gave the team the chance to change other things, and that Fuji Television's characters wouldn't be popular in America where Mario's would. Kohler writes that Tanabe's team added enemies and visual nods to the Mario games, and greatly improved the animation and sound effects. | after the Fuji dealafter the Fuji dealafter the Fuji deal | Interview |