Rainbow Road

Rainbow Road is the name of several levels featured in the Mario Kart racing game series, developed and published by Nintendo. Usually presented as a rainbow-coloured racing course suspended in space, Rainbow Road is widely recognized as one of the most iconic staple elements of the Mario Kart video game series.

Characteristics
Rainbow Road customarily appears as the final brand new track of each Mario Kart game and the final race of the Special Cup. It typically is among the most difficult to complete, since most Rainbow Road tracks often have little to no guardrails to prevent the player from falling off the edges of the track, and oftentimes feature tight curves, steep slopes, and wavy grounds. Most Rainbow Road courses have been revised to be featured more than once throughout the series, the original one appearing in four distinct games and the second one three times.

Appearances
Rainbow Road appears as the final level of every major Mario Kart game except Mario Kart Arcade GP DX.

Super Mario Kart
Rainbow Road originally appeared as the final level of the Special Cup in Super Mario Kart and is the only course in the game not to have numbered variants, since it appears only once. It lacks guardrails completely and is filled with sharp-90 degree turns with a few jumping blocks on the track's surface. Since floor behaviour is dictated by tile type in the original Mario Kart, the slightest "black tile" would send the racer off the track, forcing its player to wisely search the apex in every curve. Highly favoring the high-speed heavy characters (Bowser and Donkey Kong Jr.), this track saw all lap records performed with these two characters.

Rainbow Road also features Star Thwomps which - unlike the regular Thwomps met in Bowser's Castle levels - can deal more damage and spin racers out on the ground.

This track was later remade in Mario Kart: Super Circuit as an Extra track, in Mario Kart 7 as a retro track, in Mario Kart 8 as part of the Legend of Zelda x Mario Kart 8 DLC pack, and in Mario Kart Tour, making it tied with Super Mario Kart's Mario Circuit 3 for having the most appearances in the series. The remakes in Mario Kart 7 and onward replaced the yellow bumps with ramps following Mario Kart Wii's addition of the Jump Boost feature in the series, had the Star Thwomps create ripples on the track for racers to make stunts off of, and added a ramp in the last fork of the road for an additional shortcut option.

Mario Kart 64
The next Rainbow Road featured in Mario Kart 64 as the final track of the Special Cup. It is not only the longest track in the game, but also the longest track of the entire Mario Kart series, with each lap taking around one and a half to two minutes to complete without the use of shortcuts. Unlike other incarnations of the course, this version is completely covered in star-shaped guardrails. While racing, players can see neon light pictures of all 8 playable characters of the game and avoid Chain Chomps scattered throughout the course. This version's main melody is also incorporated into the music for the Mario Kart: Double Dash!! and Mario Kart 7 versions of Rainbow Road, becoming the officious "Rainbow road theme". The level also appeared in F-Zero X's Joker Cup. If the player had the 64DD expansion features, they could also listen to a rock remix of the original melody.

This Rainbow Road was later remade as a retro track in Mario Kart 8 as the final track of the retro Lightning Cup with drastic visual and gameplay overhauls. No longer set in black background, but sky-high above the original course Toad Harbor at night, the track is now broken into three sections of a lap instead of three whole laps, incorporates the game's hang-glider and anti-gravity mechanics, and most of the guardrails have been removed. The Chain Chomps now bounce on the track and create ripples, and there is a flying train operated and ridden by Toads that toss coins toward the racers. The neon lights of the characters are replaced with fireworks drawing their faces as they explode.

Mario Kart: Super Circuit
For a return to the original flat format (despite allowing doubled map size) introduced in Super Mario Kart, the final track of Mario Kart: Super Circuit (Game Boy Advance) lines the course with jumping humps, giving players a chance to get back on the course or take shortcuts with a Mushroom. On top of the boost panels and ramps littered throughout the course, there are also falling stars that can harm players and Thunder Clouds that can shrink them if they come into contact. The background features Bowser's flying castle from Paper Mario.

Mario Kart: Double Dash!!
The Rainbow Road in Mario Kart: Double Dash!! for the GameCube goes largely downhill before the players enter a helix filled with dash panels and a large pipe that launches players to the top, similar to the game's DK Mountain track. The track takes place above this game's Mushroom City at night and features floating sculptures of items that can rain Star power-ups that racers can pick up. The track's music (which features a remix of Mario Kart 64's Rainbow Road near the end) would be featured in every Super Smash Bros. title going forward beginning with Super Smash Bros. Brawl.

Mario Kart Arcade GP
Namco's arcade game Mario Kart Arcade GP features a final cup inspired by Rainbow Road called the Rainbow Cup. The Rainbow Cup features two courses called Rainbow Coaster and Rainbow Downhill. Similar to the 64 version, both tracks are completely covered in guardrails making it impossible for racers to fall off. The first half of the course appears to take place at a space station and features floating sculptures of items similar to the Double Dash!! version. For the second half, racers are warped to another world. In the first two variants, it takes place in the sky that features Toads on floating islands, flowers, and beanstalks in the background. The second two variants take the racers to a more aquatic environment with coral and Warp Pipes surrounding the racetrack. For the cup's challenge game, the player has to defeat a robotic version of Mario called "Robo Mario" in a race.

In the game's follow-up, Mario Kart Arcade GP 2, the track underwent a couple of changes. The tracks now had three laps instead of two, and the second variant of the two courses replaced the aquatic theme with a sky temple setting.

Mario Kart DS
The track's incarnation in Mario Kart DS is largely similar to the version in Mario Kart: Double Dash!! with its sharp turns, helix, and dash panels. What distinguishes it from previous versions is that it features a vertical loop and corkscrew, which were the first and only inversions on a track in Mario Kart history before Mario Kart 8 introduced anti-gravity. Rainbow Road DS is also the only Rainbow Road in the series whose layout could theoretically work as a roller coaster layout, with a curved initial climb, a downfall larger than the loop and other hilltops, each slightly less tall than the previous one so that a train could pass each and return to the start on its own.

Mario Kart Wii
In Mario Kart Wii, the track is located above Earth's atmosphere, sending racers burning down toward the planet if they fall off. The course is heavily inspired by Super Mario Galaxy, as there are Star Bits floating throughout the track and the climax features a Launch Star that launches players upwards similar to the Mario Kart: Double Dash!! version. It also features many ramps that racers can perform tricks or take shortcuts on, as it was the first game in the series to introduce tricks. The track was later remade for Mario Kart Tour with mostly visual improvements and for Mario Kart 8 Deluxe featuring its anti-gravity mechanic throughout the track.

Mario Kart 7
For the first time in the series, Mario Kart 7 broke the Rainbow Road track into three sections rather than three whole laps. It takes place in outer space, where racers will avoid asteroids, drive on the rings of Saturn, and avoid low-gravity Chain Chomps on the moon. The climax features a turning tunnel with dash panels that give players the option to go back on the road or take a glide ramp. The track was later remade for Mario Kart Tour and Mario Kart 8 Deluxe, with the latter featuring the game's anti-gravity mechanic on the moon.

The course was also featured as a stage in Super Smash Bros. for Nintendo 3DS. Fighters battle on a flat platform that travels throughout the course similar to the F-Zero stages and avoid racing Shy Guys competing in a race.

Mario Kart 8 / Mario Kart 8 Deluxe
In Mario Kart 8 as well as Mario Kart 8 Deluxe, the track uses three whole laps again instead of lap sections, and there is again a planet in the background with a higher resolution than the one from Mario Kart Wii. This track is the first one to exploit the idea of gliding upon solar panels on a space station, giving a plausible explanation to the track's premise of a rainbow-colored track suspended in outer space. The ground uses quadratic tiles in resemblance to the original Rainbow Road (Super Mario Kart). At the start/finish line, the track crosses through a space craft filled with Toads who sit on tribunes as on a normal racetrack. Several more space ships carry parts of the track, most notably the one with two circular conveyor belt rotating rings in opposing directions which can speed up or slow down the vehicle that drives upon. As with other Mario Kart 8 tracks, Rainbow Road's surface is wildly twisted, forcing racers to make use of the new anti-gravity feature. At a location, two separated parts of the track cross nearby in different angles, and distant parts of the track can be seen ahead from far away. According to Mario Kart 8 Deluxe producer Kosuke Yabuki, the development team's goal was to create a version of Rainbow Road with a "near-future" aesthetic when anti-gravity controls were added.

Mario Kart Tour
Mario Kart Tour features two courses based on the original Rainbow Road from Super Mario Kart. Labeled as "remix courses" (abbreviated to "RMX courses") these courses use a different layout compared to the original, and feature new mechanics, such as gliding and bouncy mushroom platforms. These courses are named RMX Rainbow Road 1 and 2, and share their music with the course they are based on.

The Super Mario Bros. Movie
The course makes an appearance in 2023's The Super Mario Bros. Movie as "The Secret Path", on-which Mario, Princess Peach, Toad, Donkey Kong, and the Kong Army battle Bowser's army as they unsuccessfully attempt to storm his castle. Mario and Donkey Kong are thrown off the course by a Koopa General with a blue shell in a kamikaze attack. When developing the film, directors Aaron Horvath and Michael Jelenic sought to recreate Rainbow Road's sense of danger and challenge as they described it as "The most unforgiving course in the series". The Rainbow Road scene in the film was the most ambitious animation sequence that Illumination had undertaken compared to their previous films.

Other appearances
Rainbow Road and variations of the course has made several appearances in other Mario and Nintendo-related titles, including F-Zero X, Super Smash Bros. for Nintendo 3DS, Mario Hoops 3-on-3, Super Mario Galaxy 2, and Paper Mario: Color Splash. It also appears during the climax of the Universal Studios ride, Mario Kart: Bowser's Challenge.

Cultural impact
Rainbow Road is referenced as a part of an Easter egg included in the programming of Tesla electric vehicles. According to Tesla CEO Elon Musk, once a Tesla car's autopilot mode is activated four times in quick succession, the gray road shown on the vehicle's instrument cluster would transform into a colorful path resembling Rainbow Road, with a cowbell tune playing in the background while this mode is turned on. In commemoration of Mario Day celebrations for March 10, 2021, Hot Wheels released a Mario Kart track set based on the course on June 24, 2021.

To coincide with the 35th Anniversary of Super Mario Bros., an ice cream cake inspired by the track was released by Cold Stone Creamery from September 30 to December 15, 2020.

Reception
Rainbow Road has received a generally positive attention for its memorable music and unique visuals, as well as notoriety for its length and challenging difficulty. Edge Magazine described Rainbow Road as "the deadly ribbon that has entranced generations of racers". Gus Turner from Complex described Rainbow Road as "simultaneously the most thrilling and most devastating level in any Mario Kart title". Rainbow Road has appeared in multiple "top" ranking lists of the best tracks in the history of the Mario Kart franchise compiled by video game critics, including Paste Magazine, Digital Spy, Screen Rant, and GameRevolution, and TheGamer.

The Rainbow Road levels in certain Mario Kart games have received particular attention. BuzzFeed News Reporter Joseph Bernstein ranked the Super Mario Kart version of Rainbow Road #15 on his list of the "34 Video Game Levels That You Must Play Before You Die". Reminiscing the Super Mario Kart version of Rainbow Road, A. V. Club staff said the overall experience was awe-inspiring in spite of its flawed design and frustrating level of difficulty. Its music has been praised by GamesRadar Brett Elston as well as Dan Neilan from The A.V. Club, who called it as the "one redeeming quality" of a notoriously difficult track. Andrew Webster from The Verge praised the updated version of Rainbow Road for Mario Kart 8 as the best example of its "impressive new track design" and called it a vast improvement when compared to previous instalments. On April 28, 2017, Rainbow Road was voted as the best course in Mario Kart 8 Deluxe by UK players.

Not all reception towards Rainbow Road has been positive. Ben Lee of Digital Spy as well as several US Gamer staff members considered the Nintendo 64 version of Rainbow Road to be one of their least favorite tracks in the history of the Mario Kart franchise.