Super Mario Bros. 2 was technically not a unique Mario game, but rather an enhanced port of a Japanese game called "Yume Kōjō: Doki Doki Panic", translated to English as "Dream Factory: Heart-Pounding Panic". The "Dream Factory" part of the name refers to an expensive 1987 Japanese expo organized by Fuji Television called the Communication Carnival Yume Kōjō '87 that showcased various upcoming programs. As part of an ongoing license cooperation between Nintendo and Fuji, the festival's four main mascots became the playable characters in the game, while all other characters were created by Nintendo. It was ported and released in North America with Mario, Luigi, Princess Toadstool and Toad replacing the mascots. This was released in place of the Japanese Super Mario Bros. 2 (known in the US as Super Mario Bros.: The Lost Levels) because Nintendo of America considered it to be too difficult and too similar to the first Super Mario Bros. to compete with rapidly advancing games from rival companies.