Sonic the 3D Hedgehog: One World for All is a sequel to Sonic the 3D Hedgehog, a Sonic game by Fusion Thunder Games that was meant to be released for the Sega Saturn following the cancellation of Sonic X-Treme, but never saw the light of day until June 10, 2012. Released on March 19th, 2013 for the Wii U and 3DS, the game features a co-operative play system, allowing up to 4 players to get a cut of the action within the adventure both locally and online.
A month has passed since Sonic and friends defeated the mighty dangerous ogre, Ogarate, in the original Sonic the 3D Hedgehog, and they have taken some time off to relax. However, just as they are about to wake up from a relaxing nap, a strange and mysterious woman covered in shadow appears before Sonic, Tails and Amy and warps them to a strange world, filled with dark clouds. She introduces the trio to the Malice Gang, comprised of herself, a medic hidden underneath a hat and a trenchcoat, the revived Ogarate and Tiara Boobowski. Sonic, shocked to see Tiara there, believes that the woman either rebuilt that robot impersonator from Dreaded Deep or brainwashed the real Tiara. The three are told that as they speak, they are infected with a virus that will take them out in a week, and once it is done with the heroes, it will spread about and terrorize all of Mobius. They are challenged to go all over North Island, Angel Island and the new world, Murtopia, to collect the eight (not six) Chaos Rings. Sonic, Tails and Amy are then teleported to North Island and find themselves in a place they didn't travel through before, Grand Seaside, an aquatic paradise with a crystal castle and a giant spring. This is where their next adventure begins.
Meanwhile, Knuckles, the guardian of Angel Island and the Master Emerald, senses trouble at North Island, so he decides to leave his position and call upon his friends, the Chaotix. Knuckles chooses who stays behind to protect the Master Emerald and who goes with him to assist Sonic, Tails and Amy before heading out.
Throughout each location that Sonic, Tails, Amy and Knuckles travel through, the Chaotix members who volunteered to assist will occasionally help out when necessary, and along the way, the foursome will have to fight hordes of killer robots, evil magic creatures, enemy vehicles and Murtopian animals.
After getting through the first two acts of Grand Seaside, the heroes encounter a giant Metal Sonic, trying to impede their path, but Sonic, Tails, Amy and Knuckles manage to take it out by working together to overcome it. After taking it out, they find out it was holding the first Chaos Ring inside it's body. After collecting it, Tiara appears before the group and congratulates them on their first victory for this adventure, then tells them that the next Chaos Ring is in Magma Mines under heavy guard by a volcanic force. The heroes and heroine trek through the mines until they reach the bottom, where the Chaos Ring is being held inside a lava wall. Trying to obtain it, a monster comes out of the lava wall and attacks. It's eventually defeated and the 2nd Chaos Ring is obtained. Afterwards, Tiara reveals herself to be the one who animated the monster and compliments the heroes for passing her "test" before leaving. On the surface, the heroes find themselves in Ringopolis, a city built by the Ring Govenors of North Island, where they learn of a new general created by Ogarate using one of the Chaos Rings to levitate the city. In the third act, the general, a big troll with rocket jets on his back, confronts the foursome and uses the third Chaos Ring to levitate them into the airborne debri. A battle ensues on floating chunks of skyscrapers, flying billboards and levitated cars. By defeating the general, the third Chaos Ring begins to break free of his control, but Sonic and Tails grab it and use it to fix up the city. Ogarate appears before the four island saviors and tells them that they're making their move on Angel Island, making Knuckles very mad. Sonic, Tails, Amy and Knuckles take a blimp in the city to Angel Island, but as they find themselves above the floating mass, they are shot down by the mystery woman and they end up in the Icecap Foundry, a factory built by the Malice Gang in the Icecap Zone prior to their first meeting with Sonic and friends. Sonic and his allies fight their way through two acts of the establishment before they confront a mechanical monstrosity that resembles an octopus. After beating it, the 4th Chaos Ring pops out of it and the foundry starts to burst into flames. Sonic is ejected out by a magical force that picks him up, along with the Chaos Ring, and helps him escape, but leaves the others inside. Sonic, panicked that his friends were left behind to perish by whoever lifted him up with a magical power, tries to dig into the rubble to find them, but to no avail. Right behind him, his friends appear and tell him not to worry. They spot the mystery woman, who runs quickly into the distance, and follow her to an abandoned mechanical site, which has been turned into a valley filled with booby traps and killer golems. At the end, the mystery woman appears before them and tells them that the armada from Murtopia has come to Mobius and will take all of the Rings from the World to salvage their world. She also reveals that while the group was collecting Chaos Rings, the Malice Gang, including herself, Ogarate and Tiara have been strengthening the viruses inside Sonic, Tails and Amy, and that the spread has already begun prematurely. Finally, she reveals that she's not the mysterious woman, as she takes off her shadow veil, revealing a massive centipede-like creature, named Pedey Pod. Pedey is defeated by the teamwork of Sonic and pals and she releases the 5th Chaos Ring. With the armada on the approach, Sonic and friends take to the skies with a boost from a nearby geyser and land on a small ship, beginning the next part of their adventure. They realize that their apparent goal now is to find an antidote before Mobius ceases to be a world that can support life. Meanwhile, inside the mothership, Tiara and the anonymous medic watch the heroes and chuckle at their efforts, commenting that their goal is "a century away from being reached", and they will die from the virus before they can find the last few Chaos Rings. A darkened cage shows three figures trapped inside, obscured by the shade. After jumping from ship to ship for two acts, the four friends reach the mothership and confront Tiara and a fight starts up. Seconds after the battle begins, Tiara falls down and cries, and the medic comes over to her side. Sonic begins a speech about why Tiara should be ashamed of her actions and her allegiance with the Malice Gang, but before he can go far, the medic presses a button and strangely, Tails, Amy and Knuckles' eyes begin to flash, and they approach Tiara. Tiara shouts "You're such a sucker, Sonic!" to the blue hedgehog and escapes through a trap door along with the medic. Tails, Amy and Knuckles are revealed to be transforming robots and combine together to form a war machine with shoulder turrets, rocket launcher hands and electric generators for legs. Sonic runs away from the machine until he discovers the real Tails, Amy and Knuckles in a cage with bars so strong, even Knuckles can't break free. Sonic tricks the machine into busting them out with it's rockets, reuniting the four friends. Once again, their teamwork triumphs and the machine breaks down. Tails explains that when Sonic was thrown out of the Icecap Foundry, Tails, Amy and Knuckles were rescued by Tiara, but she also had them imprisoned and sent the doppelgangers to fool Sonic and eventually assasinate him on the mothership, where the real ones could watch. They head to the control room where Chaos Ring number 6 is located and they grab it. After doing so, they activate a switch that opens the door to Murtopia, the world where the last two Chaos Rings are, and head over there in the mothership. Upon arrival, they learn from a giant monitor that Mobius is dying and all the rings are being moved to Murtopia while the virus eats away at Sonic's home. Sonic, Tails, Amy and Knuckles are also feeling that way, noticing that the virus is beginning to take their toll on them. Despite this, they put their feet down and make their way through the Luna Palace. When they reach the third act, they find a stash of rings taken from Mobius. However, an antidote for the virus, which they need at the moment, is nowhere to be found. The medic appears before them and claims that he has just the cure for them. Unfortunately, he's not willing to come to a compromise on any offers the heroes wish to make, so he decides to kill the heroes using his personal fighting mech powered by dozens of rings and the 7th Chaos Ring. By working together once more, the mech is defeated, releasing the Chaos Ring that was inside it, and the medic falls to the ground, releasing the cure. Tails grabs it and opens up the vial it's contained in, putting a small drop of it into the mouths of himself, Sonic, Amy and Knuckles. The cure works, but the medic begins to laugh and get up. His trenchcoat and hat have come off after the explosion of his mech and his impact with the floor, and he's revealed to be none other than Dr. Eggman, the evil scientist who caused Sonic and company so much trouble in the past. He tells them that the potion will only temporary get rid of the virus. He says that in a matter of time, the virus will ignite again at full force, and inorder for it to be totally healed, the antidote will need more to it, but doesn't reveal the next piece of the cure. Sonic, Tails, Amy and Knuckles figure that they'll find the answers on the next step of their journey and that they better hurry along while the limited vaccine in their bodies is still active. Tails decides to keep the vial incase of future need for it. Their next destination, which they arrive at via hoverbus, is Anarchy Resort, where they know is the location of the final Chaos Ring by just looking at a glowing light that rests on top of a tall building. Following their rampage through the vibrant and eye-catching sights of the resort, they reach the roof of the casino in Act 3, where the last Chaos Ring is resting. As Sonic and his team approach, they feel the virus exponentially kicking in again. Ogarate appears before them and decides to fight them in their dying moments. He uses a gravity shifter to take them to an upside down battlefield, where they duke it out, with Ogarate claiming that there's no strength in numbers. Despite the heroes being weakened, Ogarate falls once again. The heroes fall back on to the roof of the casino as the gravity shifter's effects are reversed, while Ogarate falls into a deep pool below. Sonic and friends acquire the final Chaos Ring at last, marking the completion of the Malice Gang's challenge. The 8 Chaos Rings ignite a flare and shower streaks of light all over the heroes, aswell as the vial containing the cure. The cure lights up, implying that it may work now. Tails gives a drop to himself and each of friends, using up the last of what's in the vial. As a result, not only does the virus rapidly weaken, restoring each of the heroes, but the four friends acquire Crystal Rings that attach around their wrists, granting them the mystic art called "One World for All", a reward for finding all of the Chaos Rings and keeping their bond strong throughout the whole adventure. On one hand, the foursome has accomplished an incredible feat. On the other hand, Mobius is still dying and having all of it's rings taken away. Luckily, they are able to receive information from a screen inside the casino that tells them about Malice HQ, which happens to own a cannon that can shoot things to other worlds. Tails believes that if they can conjure another batch of the cure that saved them, they may be able to destroy the remains of the virus on Mobius from Murtopia and save their world. Taking a hovercraft, they make it to Malice HQ, where they sneak past the guards outside the perimeter, fight their way through the toughest army of Murtopian soldiers yet and emerge inside the headquarters. After they valiantly traverse through the interior of Malice HQ, they arrive in the Lab where the massive cannon is located but once again cross paths with Tiara. Sonic asks Tiara if she's the real deal or she's Ogarate's robot Tiara. Tiara replies by asking what it matters to Sonic, and Sonic takes a quick look at Amy before walking up to Tiara and grabs her, moving his mouth up to her ear. Sonic, in the most genuine way possible, whispers "because if you're the real one, you should remember... I love you.", only to be shoved back. Sonic, Tails, Amy and Knuckles stand their ground as Tiara transforms her staff into the crystal blade she used against Lord Etarago (Ogarate's true form) a month back, and they all prepare to have the fight of their lives. Through an onslaught of powerful attacks blazing and Murtopian soldiers interfering to protect the Boobowski lady, Tiara is defeated and pinned down, but not entirely out. The mysterious woman appears and seizes Sonic and friends, as Tiara gets back on her feet. Taking the quartet outside, where they are being held captive by Murtopian strongmen, Dr. Eggman and Ogarate announce that the cannon that they own at Malice HQ is part of a superweapon that the ogre and doctor worked together on since last month. They press a giant button on a console that causes the HQ to change shape, opening up to reveal a colossal hidden passage coming out from the ground. Out from the passage emerges a gigantic mech shaped like an anthropomorphic bat with blue eyeshadow, a heart shaped breast plate, a black jumpsuit, white high-heel boots and white elbow-length gloves, with the giant cannon attached to it's head via magnet that levitates the cannon into a door on the mech's cranium. The mysterious woman says "A mechanical version of me cannot ever look as astounding as this.", and she commands Tiara to take control of the mech and send Ogarate and Dr. Eggman away. Dr. Eggman is sent back to the poisoned Mobius while Ogarate is imprisoned in Malice HQ's dungeon. The mystery woman introduces herself as Rouge, a Murtopian bat, a master criminal and a lover of eye-catching items. She admits that she has been collecting Mobius' rings and other riches to add to her collection of beautiful objects and decided to intoxicate Mobius so that the collecting rate would speed up, as she finds that the Mobians will be willing to give up their most precious belongings before their demises. Finding it unbelievable how this lady could go so low, Sonic, Amy and Knuckles want to put her in the ground, but Tails advises that they get Rouge's mech out of the way as Tiara, who has taken control of it, is beginning to shoot at them. Suddenly, a bunch of Murtopian ships come flying out of nowhere and fire at the mech. The ones piloting them are Vector, Espio, Charmy, Mighty and Ray, who hijacked these ships to help out Sonic and company in a dire moment. A big ship piloted by a Murtopian ruffian comes in to defend the Rouge mech, but the pilot is dispatched by Sonic (thanks to his quick reflexes) and the three Mobian heroes plus the Mobian heroine get on board to initiate the final battle, while Rouge grabs her big guns and flies up to protect the mech and Tiara. Sonic, Tails, Amy, Knuckles and the Chaotix take out Rouge and tear down the mech from the feet up to the chest. Tiara prepares to destroy the ship with a laser beam from the big cannon, but Tails presses the eject switch before the laser blasts the ship into smithereens. They land on the head of the mech (which is the last part of it remaining at this point in the fight) and place the Chaos Rings in the cannon, but are still missing the last piece of the cure. Tails then reminds his friends that the Chaos Ring charged vaccine from before gave them the "One World for All" ability and comes to the conclusion that they had the last ingredient the whole time since that moment. Sonic, Amy and Knuckles are unsure about this at first, but Tails convinces them to try it, and before they know it, they have control over the cannon. Almost instantly, they order the cannon to target Planet Mobius and shoot it with a Virus Cure Beam. The cannon does just that, and Tiara has no control over it. As soon as the beam hits Mobius, the virus is permanently destroyed, and everyone on Mobius begins to feel better, restoring the planet to it's former glory. Even Dr. Eggman feels relieved. Sonic and friends, having pity on anyone who had to catch the virus on Murtopia, immediately order the cannon to use the Virus Cure Beam on Murtopia, which it does. Tiara, having just about enough of the Mobian heroes, leaves the mech's head and attempts to finish them off right then and there. As quick as a flash, Sonic knocks the crystal blade of Tiara's hands and Tails catches it. Sonic starts spinning into the Rouge mech head, Tails stabs it with the crystal blade, Amy smashes it repeatedly with her hammer and Knuckles punches it rapidly. They smash it up until it plummets into Malice HQ. Before it collides with the opened up villainous lair, the Chaotix, in their airships, collect Sonic, Tails, Amy, Knuckles and Tiara and move away from the mech head before it explodes, destroying Malice HQ, leaving a pile of dust in it's wake, sealing up the passage to the underground and presumably imprisoning Ogarate for good. The friends fly back to the ground to inspect Tiara, who is beginning to shake. Before their very eyes, the Mobian friends see a creature made out of Murtopian Fog pop out of Tiara's body. The creature looks for a new host until it decides to possess Amy. Before it can enter it's new host and start anew, Sonic kicks the vile thing away from Amy and Knuckles punches it into the air, sending it packing and leaving a star where it disappears into the distance.
With the Malice Gang defeated and the Sentient Fog Monster disposed, Tiara regains conciousness and sees her friends looking at her. Sonic explains the whole thing and Tiara, happy that she has been saved from a life of infamy, hugs Sonic in a burst of joy. The two spin happily and laugh, eventually getting ready to kiss, until Amy interrupts them, wielding her hammer. She throws it down as Sonic and Tiara back away, followed by the pink hedgehog going on a tangent of deserving some heartfelt respect of her own, until Tails reminds her that they have all earned respect in their own right for the hard work they've put into getting through their quest. With that, they take a group picture over at the Anarchy Resort and decide to use the mothership to take all the stolen rings back to Mobius. Behind their backs, Rouge resurfaces from below the wreckage of Malice HQ and declares "You haven't seen everything, cuties. I'm still top bat. A lady always has a couple of spare tricks in her collection, and I have plenty. You're going to love my beautiful technique." while Sonic and company (including the Chaotix) load the mothership with bags of rings. Rouge puts her right arm up and shows the eight Chaos Rings hanging on it in a row.
Once all of the stolen Mobius rings are loaded on to the mothership, Sonic and friends travel back to Mobius and fly all over the planet to return every single ring. After returning all of the stolen rings, their mothership's console receives a transmission from Murtopia. The one transmitting is Rouge, with a message to Sonic and the gang. She reveals to them that she is now in possession of the Chaos Rings and she's holding them as prizes for contestants at the Murtopia Colosseum. She demands the group to come back to Murtopia and compete for them before she decides to do something with them, such as bringing a century of chaos to Mobius. Knowing that the fate of their home world is at risk, Sonic and company take the mothership and themselves back to Murtopia, but upon reentry, the mothership is shot down by vast beam of light. The heroes survive the vessel's crash and land near the colosseumm, but it doesn't take them long to find out that their Crystal Rings are missing. With no time to waste, they head into the colosseum, where they have to get through giant corriders of different shapes, sizes and themes, fighting packs of Murtopian strongmen and fog monsters along the way. After two acts of endurance, they make it to the center, where the battlefield is, surrounded by thousands of Murtopians, waiting to see a showdown. Two towering Murtopians approach the Mobian heroes and heroine as the announcer presents Sonic, Tails, Amy and Knuckles as the challengers. A flying figure swoops down as the big Murtopians raise their arms and lower them, presenting the colosseum champion, Rouge. Rouge agrees to challenge the heroes and heroine, engaging them all in what seems like their last battle. Rouge shoots at them, shifts gravity occasionally, tries to physically attack them, works out her allure and even plants lethal bombs everywhere, trying her best to subdue her adversaries. At the end of the day, though, Rouge is overwhelmed and defeated. Before any congratulations are heard, Rouge gets back on her feet and starts talking, but she sounds like she's talking in the voice of another Rouge, who tells Sonic and friends that their Crystal Rings have granted her the "One World for All" technique and she's currently using it on the Chaos Rings and the Fog Monster that used to have Tiara as it's host. Telling them that it's too late and Mobius will be at her feet even if Sonic's group does win the battle, and the Rouge standing in front of the gang makes the sound of static. The Rouge in the colosseum is revealed to be an android decoy, which proceeds to regenerate itself. The android retracts her wings into her back and sprouts mechanical wings with jet-propelled boosters and laser cannons, reveals the hoversoles on her boots, turns her hands into razor boomerang blades and opens up her breast plate, unveiling a vaccuum. The heroic Mobians smash away at the Rouge robot in another round of combat while fending off a group of robotic troopers trying to keep the impersonator out of harm's way. Ultimately, the robot is smashed until all of it's synthetic skin, fur and clothes are knocked off it's honest-to-goodness metallic hide, and it's beaten again, resulting in a malfunction that causes it to suck it's weaponry and appendages into it's chest until it's clogged and it finally explodes, colourful embers flying.
Being declared the winners, Sonic, Tails, Amy and Knuckles rush up to the prize booth to grab the eight Chaos Rings, but they soon discover that they were fakes, and the whole thing was just a set up for Rouge to plot against Mobius with the Crystal Rings and the real Chaos Rings in another place. Tiara, who watched the preceding fight and received permission to enter the arena after the Rouge robot was defeated, approaches Sonic and tells her and the others about the whereabouts of the real Rouge. She received information from the Chaotix regarding a night club near Anarchy Resort called Soiree Night. She agrees to help them find the safest way inside and gives them a ride on the nearest hovercraft. Upon arrival, Sonic and his partners are directed to a secret passageway that should get them inside the night club without much trouble. They get inside, but they are spotted anyways. What follows is two acts of fighting through puzzling areas, anti-gravity rooms, elevator shafts containing waves of Murtopian Elites, Fog Monsters and Mecha Rouges (which are weaker than the one in the colosseum). In the final act, Sonic, Tails, Amy and Knuckles reach Rouge's office, with Tiara shortly joining them by falling through an air shaft. Rouge is nowhere to be found, but the Crystal Rings are laying on a desk, wide open for the taking. Immediately, they grab them and put them back on their wrists, reclaiming the crystal energy within. Right after, though, they are teleported to a massive room with a king-sized platform in the middle of it. On the platform, they come face-to-face with the true Rouge the Bat, who has increased in size by two times the height she was before and is wearing small versions of the Chaos Rings on her fingers. Inside her body is the Fog Monster that they defeated back at Malice HQ, but instead of making a puppet out of her, it's only making Rouge more powerful. It turns out that with the Chaos Rings on her, the Fog Monster won't take away Rouge's control of her body, but make her strong enough to make fuel for her own personal planet killing weapon, the Atmostroyer, which she started on a long time ago and finished with help from Ogarate and Dr. Eggman long before this adventure began. She admits that she never wanted to use it, but has decided to take a risk and fire it up, all for the sake of recollecting what she believes is only hers to keep. She even lets out that she wants to be the youngest successful crime boss in Murtopia's history. After that last sentence, Sonic and his pals get tired of hearing the speech and prepare themselves for what is apparently their REAL last battle. The fight is arduous, and Rouge has a lot of tricks up her sleeve along the extra strength she's gained from her increased size, the Fog Monster and the Chaos Rings, but the four of them outnumber the opposition and knock Rouge down, until she decides she doesn't want to play anymore charges a ton of Chaos energy into the Atmostroyer, preparing to warp the ensuing laser beam to Mobius and permanently corrupt it's atmosphere. Before she can succeed, she is taken out and knocked off the platform, interrupting the charge and sending Rouge down into the abyss. The platform their standing on lowers down into the field of light below, where Rouge fell. Sonic, Amy and Knuckles think it's over, but Tails is not sure. Without warning, Rouge emerges from the field, now with a crystal-like appearance, oversized angel wings, completely green eyes with red streaks of Chaos Energy emitting from them, and she's still two times bigger than her normal size. As a last resort, Sonic, Tails, Amy and Knuckles use the Crystal Rings to activate "One World for All" at the same time, transforming them into Crystal Sonic, Crystal Tails, Crystal Amy and Crystal Knuckles. Tiara then comes up with an idea and tells her friends to hold hands, convincing them to do so in the span of a few seconds, telling them to trust her. She strikes them with her Crystal Blade, and after a burst of light, Sonic, Tails, Amy and Knuckles have grown angel and phoenix wings made out of blue, yellow, pink and red auras respectively, turning them into the strongest combined force in both Mobius AND Murtopia, with granted extra strength, extra speed, flight and the final technique, "Two World Nova", which they need to defeat Rouge and dispose of the Atmostroyer. After the toughest fight yet, Rouge is defeated and Sonic and friends perform a final strike which opens a gateway to a void of crystal, sucking them in along with the Atmostroyer. In the void, the Atmostroyer explodes and Rouge returns to normal, releasing the Chaos Rings, which change back to their regular size, and the Fog Monster, which dies in the void. Before they know it, they're back on Mobius, in the middle of Westside Island. Rouge eventually pays for her crimes and is taken in by the authorities. Tiara goes back to North Island to find places to keep the Chaos Rings, Knuckles goes back to Angel Island, the Chaotix part ways and Sonic, Tails and Amy return to where they started: getting up from a nice slumber.
A month later, Rouge is released from prison, having attended a seminar while in custody, and she has officially changed for the better. Dr. Eggman has built a new machine powered by the Chaos Emeralds and is planning to unleash a new rain of havoc on Mobius. Tiara has invited Sonic over to a secret lunch on North Island, where the two eat and talk until they trade kisses. Meanwhile, back on Murtopia, in the ruins of Malice HQ, Ogarate climbs out from the rubble that was once the Malice HQ building and the enormous Mecha Rouge, and he looks around until he grows angry and yells viciously into the air. He vows "I'm still not faltering yet!" and the game ends.
The gameplay is very much like the original Sonic the 3D Hedgehog, only this time around, the game features local and online co-op play, allowing other players to tag along with Player 1. If Player 1 is alone, they will go through the game playing as one of the protagonists. The playable characters include the titular hero, Sonic, his intelligent best friend and sidekick, Tails, his upbeat admirer, Amy, and his strong, if reckless friendly rival, Knuckles, each with their own statistic differences and abilities. If there is more than 1 player, they can work together to perform different tricks, make combat easier and enhance interaction in certain game sequences. If a certain player falls far behind, they will automatically be pushed up to the player in the lead. A couple of members of the Chaotix will, at some points, assist the player(s) in any way they can, like providing items, defeating hordes of enemies with surprise attacks or manipulating the environments to help Sonic and company with their progression. Whoever from the Chaotix group is active and inactive can be changed to suit the player's preference. Power-ups return, and they can be useful for taking out the larger hordes of enemies that appear later in the game, finding secrets and uncovering well hidden items. Each character in the game is represented by symbols of different colours and shapes. Sonic has a blue triple arrow, Tails has a yellow tornado, Amy has a pink heart and Knuckles has a red diamond. Every stage in the game has two acts worth of platforming and action gameplay along with a third act that's meant for hosting a boss battle. Completing a stage (except for the last three) awards the player(s) with one of the eight Chaos Rings, the items required to progress through the game and finish it. Just like with any Sonic game, the players will have to collect rings to survive on foot, though sometimes, they'll have to ride in big vehicles, which possess health meters. Very late in the game, the players will gain access to the "One World for All" technique, which powers up the players' characters immensely for a certain period of time. This mystical art has greater effect when 2, 3 or 4 players use it at once. If all of the characters use it at one time, they will create a burst of light that will destroy all surrounding enemies and breakable objects and turn into their Crystal forms. At it's very peak, "One World for All" is this game's equivalent to the Super and Hyper transformations.
- Sonic the Hedgehog
- Miles "Tails" Prower
- Amy Rose
- Tiara Boobowski
- Knuckles the Echidna
- Espio the Chameleon
- Vector the Crocodile
- Mighty the Armadillo
- Ray the Flying Squirrel
- Charmy Bee
- Rouge the Bat
- Dr. Eggman
- Grand Seaside
- Magma Mines
- Icecap Foundry
- Defunct Site
- Armada Cross
- Luna Palace
- Anarchy Resort
- Malice HQ
- Murtopia Colosseum
- Soiree Night
- Giant Metal Sonic
- Fire Gobbler
- Pedey Pod
- Tiara Boobowski (brief battle)
- Doctor Decimech (piloted by Dr. Eggman)
- Tiara Boobowski (true battle)
- RB-1000000 (piloted by Tiara Boobowski) and Rouge the Bat
- Rouge the Bat(?)
- Rouge the Chaos Fog
- Crystal Fog Queen Rouge
- Light Speed Shoes (Sonic)
- Jet Anklets (Tails)
- Big Hammer (Amy)
- Shovel Claws (Knuckles)
- Sonic Wind Bracelet (Sonic)
- Rhythm Badge (Tails)
- Boomerang Glove (Amy)
- Fighting Gloves (Knuckles)
- Crystal Rings (All)
On August 25, 2014, a sequel to this game was released, titled Sonic the 3D Hedgehog: Guardians of Future Yet to Come, developed by Fusion Thunder Games once again and released once more for the Wii U and Nintendo 3DS. The co-op multiplayer of One World for All and many of it's other gameplay mechanics return, with a couple of adjustments.
- Even though this sequel is a totally new game, it uses the Classic character designs for Sonic and friends to make it consistent with the first 3D Hedgehog. For this installment, Sonic and Tails' models are ripped straight out of Sonic Generations, while the models for Amy, Knuckles, Espio, Vector and Charmy are new Classic design models.
- On the promotional poster, Sonic's eyes are black, even though they turned green near the end of the original Sonic the 3D Hedgehog.
- Tiara now wears a dark bikini top, a pair of trousers and boots in this game to compliment the fact that she has turned evil.
- In this game, Rouge the Bat claims to be a resident of Murtopia rather than Mobius or Earth.
- Just like the original Sonic the 3D Hedgehog, an evil Tiara is a boss, sporting two phases. The main difference though is that in the original, it was a robot while in this game, it's the real one under a monster's influence.
- The Crystal Rings resemble Sonic's Crystal Ring from Sonic Adventure.
- Even though the dangerous virus supposedly made Mobius' atmosphere almost completely toxic by the time the Rouge mech battle began in Murtopia, everyone on Mobius appeared to be somewhat healthy and alive the moment before it was cleansed and after the virus met it's end.