Shuttle loop

Shuttle Loops, also called Loops, are a common gameplay elements seen in almost every game in the Sonic the Hedgehog series, which are seen in numerous places around the world of Sonic the Hedgehog. Shuttle loops are different-sized landforms of unknown origin in the zone's or stage's scenery, that have a hole of loop-de-loop which the playable character can run through as a part of the path. Shuttle Loops usually appear in numerous different versions crafted out of the landscape, though there are also found Shuttle Loops in industrial, futuristic or urban-type of levels as well.

Shuttle loops have been introduced in the original 16-bit version of Sonic the Hedgehog. Besides having appeared in the games on countless occasions, Shuttle Loops have also made numerous appearances in other media, where they are not seen to have much purpose.

Overview
In Sonic the Hedgehog series, shuttle loops are seen in almost every platform title and even in some spin-off games. While not every level of each game have shuttle loops, they are seen to be one of the most common elements in the series. The earlier games in the Sonic the Hedgehog series for the Sega Genesis featured more developed game engine with pinball-based physics than any video game before.

In order to pass through a shuttle loop, a player must move at sufficient speeds in order to remain in contact with the surface of the loop, and will then exit on the other side. If a playable character is not moving fast enough, the playable character will fall down out of the loop, or not be able to scale the slopes. When moving through a shuttle loop, the player is able to either run or roll, if moving fast enough, through it. Also, similar to the real-life phenomenon of moving downhills, the shuttle loop can give the playable character more momentum should the player perform Spin Attack while moving through loop-de-loop. Numerous shuttle loops can also be differently formed with longer loop-de-loops, which requires more momentum on the player behald to be gained, before the player can get through it.

Most of the time, shuttle loops have a certain amount of Rings set up in line on their loop-de-loops, which the player can collect by moving through them.

In some cases, the shuttle loops have flat platforms above the loop-de-loop that the player can stand on. On such platforms, there can usually be found a huge amount of Rings, monitors with different power-ups or objects to be used, and even alternate pathways that the player can access. Because the player cannot reach the flat tops of the shuttle loops by jumping, there are always moving platforms nearby the shuttle loops that can take the player to the top of them. In numerous games, however, the shuttle loops do not have platforms above it to move on or are part of the ceiling of the level. Also, in a few games, alternate pathways can also go sideways or through the hole of loop-de-loops.

In later games, especially 3D games, there can usually be found a dash panel just before a shuttle loop begins, eliminating the need for the player to gain a momentum before entering a shuttle loop. Because of this, backtracking in the levels of the 3D games can be hard, if not impossible. Games such as Sonic 3D Blast and Sonic Chronicles: The Dark Brotherhood have automatic sections of the shuttle loops where the playable character goes through them to another section of the level without the player having to control to the character.

Stages with Shuttle Loops

 * Green Hill Zone
 * Star Light Zone
 * Emerald Hill Zone
 * Chemical Plant
 * Hill Top Zone
 * Angel Island Zone
 * Launch Base
 * Sandopolis Zone
 * Emerald Coast
 * Speed Highway
 * Seaside Hill
 * Ocean View
 * Westopolis
 * Leaf Storm
 * Water Palace
 * Mirage Road
 * Night Carnival
 * Huge Crisis
 * Altitude Limit
 * Dead Line
 * Forest Falls Zone
 * Colosseum Highway Zone
 * Sky Park Zone
 * Crystal Mountain Zone
 * Death Yard Zone
 * Meteor Base Zone
 * Blue Coast Zone
 * Sunset Forest Zone
 * Neon Palace Zone
 * Frontier Canyon Zone
 * Mystic Haunt Zone
 * Chaotic Inferno Zone
 * Frog Forest
 * Hang Castle
 * Windmill Isle
 * Rooftop Run
 * Skyscraper Scamper
 * Eggmanland
 * Molten Mine
 * Tropical Resort
 * Sweet Mountain
 * Planet Wisp
 * Radical Highway
 * Machine Labyrinth
 * Sylvania Castle Zone
 * Crisis City (Sonic Generations)
 * Windy Hill
 * Desert Ruins
 * Silent Forest

Trivia

 * One of the many unfixed glitches in Sonic the Hedgehog (2006) involves any of playable character in the game being able to walk, even stand on upside down at shuttle loop without falling down as it were solid ground.
 * In Super Smash Bros. Brawl, a Shuttle Loop can be seen in the background of arena Green Hill Zone with Tails, Knuckles, and Silver seen running through it constantly.
 * In some of the 2D side-scrolling Sonic games as the character runs on a loop, if the player inputs the character to jump while at the center of the loop, the character will actually accelerate.