Mushroom Kingdom III

Mushroom Kingdom III is a starter stage in Super Smash Flash 2 based on the overworld levels of Super Mario Bros. 3. It was originally introduced in v0.8a as a replacement for, before it returned in the Beta version.

Layout
The stage features a large gap in the middle, with solid terrain only being located at the edges of it. Above this gap, many blocks appear. Those blocks can be broken by jumping into them or attacking them. Occasionally, a P-Switch will appear at the edges of the stage. If pressed by any player, it will destroy all the remaining blocks at once, effectively reducing the area of the stage. All blocks will reappear given a certain time after destroyed. The stage also has a platform which moves back and forth once a character stands on it.

Music

 * The main music track is Hammer Bros. Battle!, an electronic rock remix of the theme that plays when encountering a Hammer Bro on a world map in Super Mario Bros. 3.
 * The alternate music track is Overworld, a chiptune orchestral remix of the ground theme from Super Mario Bros. 3.

Tournament legality
This stage is banned in competitive play. The stage has walk-off edges, a central pit dividing the main platform, and blocks that can create caves of life when spawned. This leads to a stage where players can get ridiculously early horizontal KOs, survive for long amounts of time in the center, and camp as much as they please. Overall, a terrible stage for competition.

Origin
The stage originated from Super Mario Bros. 3 for the Nintendo Entertainment System. The stage is based on one of the first levels of the game.

Breakable blocks have been a mainstay in the saga since Super Mario Bros., and they are heavily featured in classic Mario stages in other  games. P-Switches were also introduced in Super Mario Bros. 3, allowing a player to morph all blocks into coins (and vice versa). In Mushroom Kingdom III, a P-Switch spawns, allowing players to destroy all remaining blocks at once, but without leaving any coins.

Trivia

 * This stage's current design is strongly inspired by the Mushroom Kingdom stage from Super Smash Bros. Melee (not to be confused with the identically-named N64 stage) and has a similar, though not identical, layout and hazard. The primary differences include slightly different positioning of the blocks, along with the center region of III being more blocks and a moving platform instead of solid ground, along with the added element of the P-Switch.