Super Mario Bros. 2 is the second game in the Super Mario Bros. series. It originally was for the Nintendo Entertainment System, but was subsequently ported to many other systems.
Development
Super Mario Bros. 2 has been a topic of much confusion in the Mario world. The original Super Mario Bros. 2 was released in Japan, but Nintendo apparently decided it was too challenging for UK/US players, so it was not released in the UK or US. However, Nintendo was already working on Super Mario Bros. 3 and they had not released a SMB 2 in the UK or US yet. They needed to make a game which was quick to make, so they took Doki Doki Panic, replaced all the playable characters with Mario characters and called it Super Mario Bros. 2.
The Japanese SMB 2 was also released outside Japan as Super Mario: The Lost Levels, as a part of Super Mario All-Stars. It was also released on Super Mario Bros. Deluxe as Super Mario Bros. for Super Players.
Super Mario Bros. 2 has "accidentally" brought many characters and abilities into canon in the Marioverse. Luigi's ability to Jump "slower" than Mario comes from this game, as well as Peach's occasional ability to hover in midair and pull vegetables from seemingly nowhere (Super Smash Bros. Melee). Shy Guys, Snifits, Bob-ombs, Pokeys, and Birdo effectively exploded into the Mario world because of this game. Ironically, Wart, the main villain, never reappeared in a Mario game, however was mentioned in later games.
[edit] Story
In the game, Mario, Luigi, Princess Peach and Toad travel through the world of Subcon, the world of dreams, which is ruled by the giant frog Wart. They enter Subcon through a cave they find while on a picnic trip.
They were called by the Subcons, who where captured by Wart. On their adventure, they fight Wart's army, the 8 bits, and his generals, Mouser, Clawgrip, Fry Guy, and Tryclyde.
Spoiler warning: Plot and/or ending details follow.
The end of the game shows Mario waking up. It is therefore disputable if the story of SMB 2 just happened in Mario's dreams.
Spoilers end here.
[edit] Gameplay

A screenshot from the original game.
Because the game was a clone of Doki Doki Panic, it had little in common with the original Super Mario Bros. In order to defeat enemies, the player could throw Vegetables at them, or jump on them, grab them and throw them away.
At the beginning of each level, the player could choose between the playable characters: Mario, Luigi, Toad and Princess Peach. When entering the next level or losing a life, he could select a different character again.
At the end of most levels of the game, the player fought Birdo.
[edit] Enemies
Albatoss
Autobomb
Beezo
Birdo
Bob-omb
Clawgrip
Cobrat
Flurry
Fryguy
Hawkmouth
Hoopster
Mini Fryguy
Mouser
Ninji
Ostro
Panser
Phanto
Pidgit
Pokey
Porcupo
Shy Guy
Snifit
Spark
Trouter
Tryclyde
Tweeter
Wart
[edit] Remakes
In Japan, the american version of Super Mario Bros. 2 was rereleased under the name Super Mario USA.
The game was ported to the American arcade machine, the Nintendo Playchoice-10.
It was later ported to the Super Nintendo Entertainment System, as a part of Super Mario All-Stars, and was, as a part of All-Stars, available in Super Mario All-Stars + Super Mario World. The All-Stars version showed up with updated graphics.
The Game Boy Advance remake of the game, Super Mario Advance features updated graphics, voices for main characters, and new obstacles, such as being able to collect Yoshi Eggs for an extra challenge.
[edit] Trivia
Some enemies in this game later appeared in later Mario games. This has caused much debate among fans. Many claim that since the game was a dream, the enemies should not have appeared later. However, the events of Super Mario World 2: Yoshi's Island occur before this one, and they feature the alleged enemies. This means that Mario encountered those enemies as a baby, and it makes logical sense that he would dream about them.
In the original Doki Doki Panic game, there was a third Mouser instead of the Clawgrip boss. Mario club weekly newsletter

Enemy of the week
O'chunks
O'Chunks is a villain in the game, Super Paper Mario. He is the "biggest and brawniest" minion of Count Bleck. He was once the general of an army from a certain land (the name is not mentioned). He led a force of a thousand strong across the enemy lines. Unfortunately for him, one of his advisors sold him out and all of his men fell to the enemy (the enemy's name is not mentioned either). Count Bleck may have played upon his shame and depression to enlist him in his services.
He speaks with a stereotypical Scottish accent, and seems to be the least intelligent of Bleck's minions. Despite his strength, he is usually very easy to defeat. He is fought four times in the game.
When fought for the first time, O'Chunks will attempt to Ground Pound, shoulder-ram and toss Mario. Every time he successfully tosses the plumber, despite only one damage being done, he performs an amusing victory dance. He had twenty HP in this battle.
After the first battle, O'Chucks mistakes Mario's name for Maria. Interestingly enough, when O'Chunks throws Princess Peach, he merely tosses her sans the spinning and victory pose.
He is not encountered again until Chapter 5. In 5-2, he attacks the heroes, but loses once again. He asks them to finish him off because he failed the count, but Dimentio then appears, offering him a chance at redemption. O'Chunks is fought again in 5-4, this time brainwashed by a Floro Sprout. He randomly shouts out the names of vegetables in this form, which Dimentio nicknamed O'Cabbage.
O'Chunks is fought for a fourth and final time in Castle Bleck. Here, he faces off against Bowser in a one-on-one fight as the bigger Super O'Chunks. When he loses, the ceiling starts to collapse. O'Chunks, however, holds it up, out of honor for Mario's party. Bowser however, helps him, and after a pointless display of brawn and willingness to sacrifice themselves between the two, the ceiling presumably crushes them both.
However, it is revealed that he (along with Bowser) survived when he appears to support Count Bleck in Dimension D. He and Mimi give the count and Tippi enough hope to restore the Pure Hearts, thus helping to defeat Super Dimentio.
After the game is completed, he may be found on the third floor of Flipside, searching for Nastasia (ironically enough, she's in the exact same place in Flopside).
It is hinted several times that he might have a crush on Nastasia.
[edit] Trivia
Though very likely to only be a coincidence, there was a tribe of American Indians in Wisconsin known as the Hochunks.
O'Chunks is the Jr. Troopa and the Lord Crump of Super Paper Mario as he was the most fought boss in the game.
Mario kart track of the week
sky garden
Sky Garden is a race course in the Mario Kart series. It first appeared in Mario Kart: Super Circuit on the Gameboy Advance, and then reappeared in the Retro Courses in Mario Kart DS. It takes place in clouds and a lot of beanstalks can be seen. It might take place in Nimbus Land or Sky Land. This course has no major obstacles, although players can easily fall off of it. This course doens't seem to have an apparent theme, but it does have a few Luigi billboards during the course. There are also several shortcuts in this course.