Rainbow Road is a recurring course found in the Mario Kart series, where it closes the Special Cup and the Grand Prix seasons overall. All the versions of the track share common elements : they are all suspended in space or sky, and have a very colorful track layout, hence the name, and powerful themed music. An uplifting-themed music has remained with Rainbow Road throughout the series. The roads often have limited railing, making the course extremely hard. They are sometimes the longest in the their games, notably Mario Kart 64's version, with a length of 2 kilometers and 2 minutes laptimes.
Super Mario Kart
The original Rainbow Road is characterized by hairpin corners, splits in the narrow track and the absence of crash barriers. This makes this course hard for all characters, although powersliding skills are of a great help on this track. There are invulnerable flashing Thwomps throughout the stage, causing spinouts on contact.
This course also reappeared in Mario Kart: Super Circuit with all of the other tracks, and again in Mario Kart 7 as a retro track in the fourth race in the Lightning Cup. It also appears in Mario Kart 8 as Downloadable content.
Mario Kart 64
In contrast to the SNES iteration, the Nintendo 64 version of Rainbow Road is lined with crash barriers. A steep drop at the start can be used as a shortcut by skilled players who make a well-timed jump. Chain Chomps roam the track, which is surrounded by the enormous neon visages of the game's stars. It is 2000m (2 km) long, and is the longest track in the Mario Kart series. The course is very bouncy, making the player bounce every time they drift or hop. This is used in an exploit, that skips half the track.
This track got reused in another franchise: F-Zero X a year or two later, but also got remade with major modifications in Mario Kart 8, being converted into a single-lap course. The neon faces that appeared in the sky have been replaced by fireworks, but now some trains travel across the sky, along the first and second helixes. The Chain Chomps now bounce along the track, creating waves along the track, instead of eating through the course. The new Rainbow Road 64 has used two things from older versions of Mario Kart, namely 7, Double Dash, and the original Super Mario Kart: the city setting below the box and the original tiles pattern, although all obviously updated to new graphics abilites allowed by the new console.
There's also a couple of hanggliding sections now; one on the steep drop at the beginning of the lap, and one right before the finish line. Another new addition is the anti-gravity loop, which replace the standard helix around the smiling star from the original edit.
Mario Kart: Super Circuit
A particularly devious take on the course, with multiple shortcuts, speed boost and jump pads. However, one should be careful as once again the course has very few barriers to prevent racers from driving off the track. Bowser's starship hovers in the distance as well as the Bowser Castle from Paper Mario.
Mario Kart: Double Dash!!
This version of Rainbow Road involves racing on multiple levels, speed boosts around banked helices, chicanes and a levitation tunnel that propels racers upwards and back towards the start of the course. While many of the corners have barriers, there are holes that people can fall in. The course was the only one that took place over a city, before the idea got reused in Mario Kart 8.
Mario Kart DS
This version of Rainbow Road looks similar to a Rollercoaster in terms of layout: after a spiral structure going upwards, the karts fall down a steep fall into a 360-degree loop of turbo boosts, then a corkscrew intricated into the loop, before heading back to the finish line. Narrow places make this track highly dangerous for lighter characters.
However, this is the first version of Rainbow Road on which the rainbow pattern goes along the track, and not through it like on the previous versions.
Mario Kart Wii
Mario Kart Wii's version of Rainbow Road follows tradition and is more complex than its predecessors. It also features Star Bits from Super Mario Galaxy, though they are purely aesthetic detail and do not affect gameplay. Similar to the warp tube in Double Dash, this one contains a launch star that warps you to another track segment. The entire world can be seen below the stage along with other planets, including one that has a striking resemblance to Saturn, can be seen in the background. Unlike previous installments, this track is set very high above Earth. If the player drives off the course, he or she will burn up in the atmosphere, and Lakitu will recover the player who is still smoking as though they fell into Lava.
Mario Kart 7
Rainbow Road is featured once more in Mario Kart 7 and is again made up of multicoloured tiles. It also shows planets and rockets in the background. This incarnation of Rainbow Road, along with the tracks Wuhu Loop and Maka Wuhu, only has one lap instead of three, and is divided into sections. Unlike past Rainbow Roads, this incarnation features the player driving on non-rainbow tile surfaces such as the moon and rings of a planet resembling Saturn. The first part has the drivers race on the rainbow tiles and the second part has them race on the rings of the planet for a short time. The third part brings them to the moon with Chomps coming out of the craters, and finally the track returns to the rainbow tiles. Like in Mario Kart: Double Dash!!, the music on the course is a remix of Mario Kart 64's Rainbow Road. There are 2 different variations of this new theme. The 1st variation plays while driving on the rainbow tiles, and the 2nd variation plays during the 2nd section when the player is driving on the moon.
Mario Kart 8/Mario Kart 8 Deluxe
This incarnation of the glittering course in Mario Kart 8 and Mario Kart 8 Deluxe opts for a more realistic look now taking place on a space station with the rainbow coming from starlight reflections in the solar panels. It is a normal three lap course. Soon after the start, there is a hanggliding section into a bunch of coins. There is an alternating conveyor belt portion followed by a set of 2 paths. Depending on which conveyor is going forward, there is a boost. The 2 paths intertwine with each so one player could drive off the edge of one path to drive on to the other at several points during the section. The paths merge for the final curve leading to the finish line. The outer edge of the curve has boost pads. Toads in spacesuits watch from nearby.