<P> The game consists of eight worlds with four sub-levels called "stages" in each world ." The final stage of each world takes place in a castle where Bowser is fought above a suspension bridge; the first seven of these Bowsers are "false Bowsers" whom are actually minions disguised as him, whilst the real Bowser is found in the 8th world . Bowser and his decoys are defeated by jumping over them and reaching the axe on the end of the bridge, although they can also be defeated using a Fire Flower . The game also includes some stages taking place underwater, which contain different enemies . In addition, there are bonuses and secret areas in the game . Most secret areas contain more coins for Mario to collect, but some contain "warp pipes" that allow Mario to advance directly to later worlds in the game without completing the intervening stages . After completing the game once, the player is rewarded with the ability to replay the game with changes made to increase its difficulty, such as all Goombas in the game being replaced with Buzzy Beetles, enemies similar to Koopa Troopas who cannot be defeated using the Fire Flower . </P> <P> In the fantasy setting of the Mushroom Kingdom, a tribe of turtle - like creatures known as the Koopa Troopas invade the kingdom and uses the magic of its king, Bowser, to turn its inhabitants, known as the Mushroom People, into inanimate objects such as bricks, stones and horsehair plants . Bowser and his army also kidnap Princess Toadstool, the princess of the Mushroom Kingdom and the only one with the ability to reverse Bowser's spell . After hearing the news, Mario sets out to save the princess and free the kingdom from Bowser . After traveling through various parts of the kingdom and fighting Bowser's forces along the way, Mario reaches Bowser's final stronghold, where he is able to defeat him by striking an axe on the bridge suspended over lava he is standing on, breaking the bridge, defeating Bowser, and allowing for the princess to be freed and saving the Mushroom Kingdom . </P> <P> Super Mario Bros., the successor to the 1983 arcade title Mario Bros., was designed by Shigeru Miyamoto and Takashi Tezuka, both of whom belonged to Nintendo's Creative Department, and largely programmed by Toshihiki Nakago of SRD Company, Ltd . Though not originally using any particular character, the very deliberate creative process of what would become their next game was motivated by their technical knowledge from previous games such as Excitebike, Devil World and Kung Fu, by a desire to give the ROM cartridge format "a final exclamation point" in light of the forthcoming Famicom Disk System which was expected to become the dominant new game delivery medium, and by continuing their legacy of "athletic games" with a character running and jumping with many obstacles . Miyamoto explained, "We felt strongly about how we were the first to come up with that genre, and it was a goal of ours to keep pushing it ." The game was made in tandem with The Legend of Zelda, another Famicom game directed and designed by Miyamoto, which released in Japan five months after Super Mario Bros. As a result, certain elements were carried over from The Legend of Zelda to Super Mario Bros; for instance, the fire bars that appear in the game's castle levels began as an unused object from Zelda . Development was aimed at simplicity in order to have a new game available for the end - of - year shopping season . </P> <P> The developers started by putting together a prototype in which the player simply moved a 16 by 32 pixel square around a single screen . Tezuka suggested the use of Mario after seeing the sales figures of Mario Bros., which was still selling well throughout the previous year . The team chose to name the game "Super Mario Bros ." after deciding to implement the Super Mushroom into the game . The game initially made use of a concept in which Mario or Luigi could enter a rocket ship and drive it around while firing at enemies, but this went unused; the final game's sky - based bonus stages are a remnant of this concept . After releasing Mario Bros., the team had reflected that it had been an illogical gameplay decision for Mario to be hurt by stomping upon the walking turtles, so they decided that any future Mario game would "definitely have it so that you could jump on turtles all you want ." When designing King Koopa, Miyamoto initially imagined the character as an ox, taking inspiration from the character design of the Ox King the Toei Animation film Alakazam the Great . However, when Tezuka saw Miyamoto's design for the character, he noted that it looked more akin to that of a turtle, prompting the two to work on defining and fleshing out the character's design until coming up with his final appearance . </P>

When was the first mario bros. game released