Atlantis no Nazo (アトランチスの謎 atoranchisu no nazo?, lit. "The Mystery of Atlantis") is a side-scrolling platform game developed and published by Sunsoft and released for the Family Computer in 1986. Though the game was never released outside of Japan, a partially translated version titled Super Pitfall 2 was under development by Activision for release in North America. Though "Atlantis" could be transliterated more faithfully into Japanese as "アトランティス"(atorantisu), the game's title uses the spelling "アトランチス"(atoranchisu).
The game is set in the mythical land of Atlantis. The player controls a boy named Wynn (ウィン?), whose objective is to rescue his master being held captive in the final level. SunSoft developed the game with the intention of surpassing the enormously popular Super Mario Bros., and advertised the game with the slogan Ano Super Mario wo koeta!! (あのスーパーマリオを超えた!!?, lit. "The game that surpassed Super Mario!!" The number of levels included in Atlantis did surpass the number included in Super Mario Brothers).
Source: Wikipedia, "Atlantis no Nazo", available under the CC-BY-SA License.