Brinstar (ブリンスタ, Brinstar) is the default Metroid stage that appears in Super Smash Bros. Melee, Super Smash Bros. Brawl, and Super Smash Bros. for Nintendo 3DS. It is essentially a redesign of Planet Zebes from the original Super Smash Bros..
The stage consists of a main, rocky platform, two soft platforms on the side and a hovering metallic soft platform in the center. The main platform can be passed through from below, and it actually consists of two parts held together by a fleshy blob on the right side: said blob can be weakened by attacks, and when destroyed the main platform gets separated. The same can happen to the fleshy poles which keep the main platform and the side ones together: when they are destroyed, the platforms that were being supported tilt at a very sharp angle.
The destroyable parts will start to regenerate if they are not continuously attacked, fully growing back after a while. While regenerating, the substance that holds the stage together is fall-through.
Occasionally, an earthquake occurs and acid starts to rise. The acid deals damage and heavy knockback on touch, though it can prevent characters from being KOed on the bottom. It covers most of the stage, leaving out only the topmost platform and, if their supports are destroyed, the top parts of the side platforms. After a while, the acid subsides.
In the back of the main platforms there are some ruins and a lone Chozo statue, which occasionally gets up and walks around with no gameplay effect. The background is occupied by a large pool of acid with an unindentified fleshy being rising from it.
Brinstar is considered the best Jigglypuff and Ganondorf stage in Melee (due to rest combos and forward aerial combos with Ganon off the lava) and one of the better Mr. Game & Watch and Wario stages in Brawl (due to air camping beneath the platform).
Brinstar is the first level that the player has to venture through in original Metroid. In Metroid's Brinstar there are some rooms which feature yellow acid on the ground. If the player goes in the acid it does some damage. In Metroid II: The Return of Samus there are times where acid is in the way of the player's path. If the player kills enough Metroids an earthquake occurs and the acid goes down. Towards the end of Super Metroid, in Mother Brain's room an earthquake occurs and acid starts rising up. While the acid in this stage originated in Metroid, the acid going up and down after an earthquake could be a reference to either Metroid II or Super Metroid (perhaps more likely Super Metroid as Metroid II is set on planet SR388 while Super Metroid is set on Planet Zebes which is where Brinstar is located).
In Metroid there are secret paths that the player has to take. The secret paths usually involve laying down bombs and exploding certain blocks that lead to a new area. In this stage there are this organic material that can be broken up which could likely be a reference to those destructable blocks. Mother Brain's room in both Metroid and Super Metroid feature these things called "Zebetites" which are the life veins for Mother Brain. The player has to shoot them with missiles to destroy them. As the player shoots the veins get thinner and thinner. If the player thins it out and doesn't keep shooting they start to grow back. In this stage two similar veins can be seen. They also retain how the vein can be thinned out and be broken, but in both Metroid games when the veins break they stay broken. This stage has the vein growing back after it has been broken.
Metroid has the player collecting items through the hands of Chozo statues. Super Metroid has kept these Chozo statues except some of them come to life and proceeds to attack the player; these hostile versions are known as Torizos. There are also a few Chozo statues that carry the player across areas that the player wouldn't be able to get to. In the background of this stage, there is a Chozo statue which sits in the same fashion as seen in both Metroid and Super Metroid. There are times when this Chozo Statue comes to life and walks across the stage. This is probably a reference to the different types of Chozo statues that come to life in Super Metroid.
In the three Metroid games released at the time of Melee, the player is pretty much always traversing through the caves of planets. This entire stage is featured inside a giant cave. The final boss of Metroid is Mother Brain. As the player shoots her, parts of her pulsate. Mother Brain is also featured in Super Metroid, but she doesn't act in the same manner. In the far background of this stage is a pulsating being which shares some properties with Mother Brain. Out of all the rooms of Brinstar in both Metroid and Super Metroid not one looks similar to the overall design of this stage. 
The song that plays on this stage comes from Metroid. There are three tunes that are mixed together. The first part is the music that plays in Brinstar. The second part comes from when Samus makes her first appearance. The third and last part is the song that plays on Metroid's title screen. 
- There are several references to Mother Brain in this stage:
- The fleshy stalks that connect the platforms could reference the Zebetite barriers that Samus had to break before reaching the final boss in Metroid and Super Metroid
- The gigantic alien organism in the far background somewhat resembles Mother Brain itself. While the organism lacks several of Mother Brain's characteristics, such as her recognizable single eye, a hacked camera reveals in profile that it is actually a giant brain complete with a spinal cord (which appears to be a "tentacle" otherwise).
- Hacked cameras also reveal that the stage is actually an extremely large tunnel which strongly resembles the one from Mother Brain's appearance in Metroid. The far back of the tunnel makes a very sharp left, presumably to form a "back" of the tunnel for the sake of the game's appearance.
- If the poles on either side of the stage are broken, the platforms that were being supported will tilt at a very sharp angle.
- Near to the Chozo Statue are bricks with angry faces. These appeared in the famous "Morph Ball room" in the original Metroid.
- Even though the main platform is very thick, any character can pass through it from below, but not above.
- It is possible to perform the earthquake glitch here.
- In Brawl during Training Mode, the rise and fall of the acid and the regeneration of the organic parts are not affected by the player's choice of speed.
- When you hack the camera, you may zoom out immensely and see that the backround is actually a huge tunnel, without platforms.
- If the game is hacked to have Master Hand or Crazy Hand and they get KO'd, they will bounce off the acid until the game freezes.