Sonic is picked up by a helicopter, thinking it was just for a ride, until he hears of being arrested and captured for stealing a chaos emerald. He quickly thinks of a plan to escape. (from the manual)
He takes out all of the personnel on board, busting through the door of the military helicopter and flying out before grabbing ahold of the wing. He ignores the commands of the pilot, exclaiming that the ride wasn't entertaining and that he'd rather run. He strips off a piece of the helicopter wing before flying down to the city below. This starts City Escape. At the end of the level, he lands in a circular area, ambushed by a GUN machine. After swiftly defeating it, he looks over and finds a black hedgehog perched on top, the stolen emerald in his hands. Sonic stands there in shock, before walking up to him and demanding the emerald back, charging at him. The black hedgehog says "Chaos control!" and white and green flashes erupt from the emerald. Once they are gone, the hedgehog has disappeared. Sonic sees a glimpse of him as he teleports by him. Sonic then turns around, seeing the black hedgehog on the roof and deducing that the chaos emerald is allowing him to warp. Shadow then chaos controls again, leaving Sonic to deal with the military that was called for backup.
The game cuts to Knuckles, who stands in front of a white colored bat in a pink themed outfit. She yells at him to let his master emerald go, to give it up to her. Knuckles refuses, then explains why the emerald is so important - it can neutralize the power of the chaos emeralds. Before he's done explaining, Eggman appears and lifts the emerald up. He confirms that what he took was the master emerald, while Knuckles processes what he's doing and Rouge learns of who Eggman is. The doctor says that he might have a use for it later and begins to fly off. Knuckles jumps up and shatters the emerald, to Rouge's despair, which causes the pieces to fly everywhere. When he lands, she shakes him and scolds him for breaking her emerald, while he tells her it isn't hers. Eggman flies away without the emerald and goes back to his pyramid base. Rouge watches him leave, then turns back and tells Knuckles that she wants all of the jewels to be hers. He gives her a warning, and Wild Canyon starts, where Knuckles collects three master emerald shards.
The next scene is Tails in his plane, flying over an ocean. Tails goes through what he is doing - he is flying to a top secret military prison island (which he heard about on satellite TV, definitely) to free Sonic. However, once he gets close, he notices Eggman harassing Amy on the landing strip. He lands in front of her to help her from Eggman. After fighting Eggman, the doctor lets them both go, giving a warning before he leaves. Tails then asks what Amy is doing there, and she was there to free Sonic as well. He leaves to break into the prison, and Amy follows, which starts Prison Lane
Sonic is pacing around in his cell when Amy drops through the ceiling, startling him. She tells him to keep his voice down, and Sonic starts complaining about the black hedgehog he saw before he was captured. Amy recalls him and Sonic asks where it went, to which Amy offers to free Sonic if he marries her, to which he immediately interjects. Amy drops it and frees him anyway, telling him that the black hedgehog was with Eggman. Sonic rushes off while Amy looks at the markings on the wall, then realize that Sonic is gone and calls him a brat. This starts Metal Harbor, where Sonic escapes the prison.
Sonic lands in a forest clearing, happy that he wasn't spotted yet, before he notices the black hedgehog not far from him. The other seems to be agitated at his presence as well. Sonic calls him a faker, which agitates him even further, which then causes them to fight. They end up exhausting one another, and while they're catching their breath, the black hedgehog recieves a call telling him to get out of the forest because it will explode. Sonic exclaims his shock, and the other hedgehog flees the scene. Sonic tells himself to find Amy and Tails and flee the island, which starts Green Forest. After Green Forest, the island blows up, showing Tails and Amy flying away on his plane, the Tornado.
The game takes a brief cut to Knuckles, who is now in Pumpkin Hill. He finds the three emerald shards there as well, and proceeds to his next location.
The game cuts to an announcement made by and displayed in the city by Eggman. He says that he will create the Eggman empire, and if the people of Earth do not comply, he will use a deadly laser to decimate them. To show it off, he blows up half of the moon. He gives a 24 hour time limit for the rulers of every country to comply before he uses the laser on Earth.
Sonic, Tails, and Amy all watched him blow up the moon. After their shock, Sonic realizes that the reason that the black hedgehog was collecting the emeralds was because they needed to power that laser to destroy the planet. Tails then takes out a chaos emerald, or what looks to be a chaos emerald. He explains that it is an almost identical replica of the gem, with the same wavelength and properties but less powerful. Police begin to apprehend the three before they split off, and Amy runs after them. This starts Mission Street.
Knuckles finds himself in the mines, shocked by how they're so complex. He takes on the challenge, and this starts Aquatic Mine.
Same from the police, Amy and Tails begin to look for the other chaos emeralds using the replica he has - the emeralds have a property of attracting one another, so wherever the emerald is attracted to, that's where the rest of them are. Tails says that they might be in space because he is not receieving any attraction to his emerald, and he contacts Sonic. Amy is in awe of all of this before Knuckles pops out of the sewer drain in front of them, commenting that he got lost in the mines. Amy tries to pull him out, but Tails exclaims that Sonic wants him to find the president (via communicator) because he broadcasted his message to the president's limo, so he drives off. This starts Route 101. Once he finds the president, Sonic shows up with him, and the duo ambush the limo he is in. They take out the transmitter in the limo and find that the announcement came from the Space Colony ARK, which was shut down 50 years ago due to an accident. They jump out of the limo, leaving the president shocked.
The gang arrives not far from a pyramid, which seems to be Eggman's base with a space shuttle in it to reach the ARK. Knuckles complains that the bat girl he was feuding with also went in, but Tails offers to find the entrance. This starts Hidden Base. After Hidden Base, Sonic enters the base and infiltrates it, which starts Pyramid Cave. After Pyramid Cave, the group finds a locked door, and Tails exclaims that they need a key to get in. Sonic tells Knuckles to find it, which starts Death Chamber. He finds three keys instead. After the stage is done, Knuckles encounters King Boom Boo, a ghost in the base. Once he fights the ghost, The gang comes back and are now faced with Eggman, who ambushed them. Sonic fights the statue that Eggman brought to life to defend the base, and they all run into the space shuttle. While on the space shuttle, it hits a meteor, and releases the master emerald shards that Knuckles collected. Knuckles, distraught at the loss of his shards, tries to steer the ship to get them, but is pulled back by Sonic. He leaves the shuttle himself to get them back.
Sonic, Tails, and Amy are now on the ARK. Tails brought along his fake emerald so that it could be placed into the cannon's core, neutralizing the energy of the emeralds that are already placed, while also planning to destroy the colony's power generator. He and Sonic split up (Tails went to destroy the generator and SOnic went to place the emerald in the core), and this starts Eternal Engine.
Back with Knuckles, he is below the ARK, near the cannon, finding his emerald shards, which starts Meteor Herd. After Meteor Herd, he finds Rouge, and proceeds to fight with her. After their fight, Rouge taunts him, falling off while trying to take a step forward. Knuckles catches her and brings her up. They get lost in each others motives for a second before Rouge breaks off and exclaims that he was just trying to touch a lady. Knuckles replies by saying that he was just saving his emerald pieces, to which Rouge gave up and gave them to him. After putting his emerald together, Knuckles apologizes to Rouge if he hurt her and leaves.
The game cuts back to Sonic, who already got to the core of the cannon, emerald in hand. He tries to remember where to put the emerald, asking Tails what he should do, before Eggman intervenes and tells Sonic to come to him, or else he would kill Amy. Sonic abandons his quest and runs back to Eggman, starting Crazy Gadget. Once he reaches the room where Eggman was holding his friends hostage, the doctor told him to give him the emerald that Sonic had. Sonic decided that if he gave the fake emerald, he would distract Eggman and the emerald would be put in to the core, neutralizing the others - killing two birds with one stone. He walks up to Eggman before he is locked in a capsule. Eggman tells him that they couldn't trick him with the fake emerald, to which Tails asks how he knew it was a fake - which confirms Eggman's suspicions. Sonic tells Amy to take care of herself, and Tails to never give up. Eggman then launches Sonic out to space. Tails, baffled that Sonic had asked him to do something, fights Eggman.
Sonic, in the capsule with the fake emerald, remembers Tails explanation of the gem. He wonders if he can pull off Shadow's chaos control, taking the emerald in his hand.
Knuckles, who had just come back from outer space, is walking through the colony, before a blinding light appears in front of him. Once he is able to see, he notices Sonic on the ground. He rushes over to him, asking if he is okay. Sonic mentions that he just chaos controlled from the capsule, then tells Knuckles to get to Tails and Amy and make sure they're okay, while Sonic attempts his last ditch effort to throw the emerald into the core. This starts Final Rush.
Once he finishes Final Rush, he finds Shadow, who exclaims that he didn't know Sonic could use the chaos control as well. Sonic tells him he's just a regular hedgehog. Shadow tells him he can't let him live, and they run off, fighting each other. Sonic manages to beat Shadow.
Tails and Amy, still in the room with Eggman, who is now defeated, are deeply saddened by Sonic's death. However, Tails' communicator rings, and he picks up the phone while Eggman weakly grabs the last real emerald. Sonic tells Tails to look outside, and the two watch the cannon destroy itself, the fake emerald taking away its power and causing it to fail. The camera zooms in on Sonic, who is hanging off of one of the antenna of the ARK, giving his classic thumbs up before the credits roll.
- There are multiple unused or beta music tracks. Some notable ones include City Escape with a guitar lead used for the Trial version of SA2, and Live and Learn, which had a nearly identical instrumental with a MIDI flute standing in for the vocals. It was probably used to determine the main melody of the song. It differs a lot from the final version. City Escape's guitar is also different from the final version, through there are more similarities between it and its final than Live and Learn's.
- As a thank you to the community for raising over $6,000 to benefit Children's Miracle Network hospitals, the official Sonic YouTube channel uploaded unheard demo tracks of various songs in the game (courtesy of Jun Senoue). The full list of these tracks are: City Escape, Mission Street, Radical Highway, and Metal Harbor. Most of these are unmixed, MIDI, and very basic versions of their final tracks, but City Escape is the only one that does not resemble its final version as much (City Escape actually resembles its Trial version, which makes sense because that disc was released a bit later than these demo tracks).
- Some stages in the game have leftovers from other stages. Shadow's White Jungle, for example, has leftovers from Sonic's Green Forest, which implies that the developers used Green Forest to create White Jungle. Missed objects like this also prevent the player from getting a perfect ring count.
- City Escape was heavily influenced by San Francisco. The devlopers visited the city and were inspired to create something similar to it in the next Sonic game.
- An amazing YouTuber to check out for a lot of cut and unused content for this game is SPEEPShighway. They have a shit load of videos about literally everything in this game, everything planned to be in this game, and everything that wasn't planned to stay in the game. Please check them out if you're interested in more beta content.
TCRF: (Dreamcast) (GameCube) (2012 Releases)
3D Models: (Dreamcast) (GameCube) (2012 Releases)
2D Sprites: (Dreamcast) (GameCube) (2012 Releases)
Ripped Sounds: (GameCube)