Flat Zone is an unlockable stage in Super Smash Bros. Melee, and the home stage of Mr. Game & Watch. Flat Zone is unlocked when the player beats Classic mode with Mr. Game & Watch. In All-Star mode, Flat Zone appears as the last stage where the player faces 25 lighter Mr. Game and Watches. Mr. Game & Watch's Target Test also takes place on a modified version of this stage. Also, two event modes in Super Smash Bros. Melee also appear fighting on this stage.
 Stage layout
Flat Zone is a small stage. In the middle of the stage there are numerous lines that characters can jump on. The lines will fade out and reappear while the characters battle. On the far right of the screen, characters can stand on the roof of the house. Characters will appears as 2-D images on the screen, and make a beeping noise whenever they walk. When the game is paused, rather than zoom in on one character, the camera zooms out to show the entire Game & Watch device being played on. The layout is heavily based on the Game & Watch game Helmet.
From 1980 to about 1991, Nintendo produced handheld devices called Game & Watch. There would be one game for each model of a Game & Watch. The games used an LCD screen, and the type was on an ordinary calculator, so the character and other moving objects could only move to pre-determined spots, and everything on the screen appeared flat. In this stage, the characters and the elements on the screen are all flat; however, items don't turn flat. The overall design of this stage is very similar to the Game & Watch game Helmet. The goal of Helmet is to try to get from the building on the left to the building on the right without get hit by falling tools. On this stage there are times where tools would appear and fall and the buildings are retained. The majority of Game & Watch games make a beep sound whenever something happens on the screen, which also happens on this stage.
A Game & Watch game was Manhole. The goal of Manhole was to try to fill in spots of sewer holes so that pedestrians don't fall in. If a hole wasn't filled the walking pedestrians would fall in the sewer. In this stage there are platforms that would appear in the middle of this stage and the character used in Manhole is seen filling in the spaces between the platforms. Another Game & Watch game was Oil Panic. The goal of Oil Panic is to collect dripping oil in a bucket and dump it to another guy holding a bucket below. If the player fails and misses the man holding the bucket, oil is dumped all over a customer at the gas station. The Oil Panic character in this stage holding an oil drum and spilling on the ground could be a reference to how a player can spill oil on a customer. When a player walks on this stage, beep sounds can be heard. 
 Tournament legality
Flat Zone is listed as a banned stage in tournaments in both the singles and doubles sets; this is largely due to the small size, which allows for very simple KOs because of closer blast-lines. Along with this, the falling tools can cause one-hit kills, and are difficult to avoid due to their falling speed.
 See Also