9 Differences Between Sonic The Hedgehog 3 And The Game It’s Based On

The most glaring difference between Sonic the Hedgehog 3 and Sonic Adventure 2 is the absence of Rouge the Bat. The Dreamcast game had two dueling stories: Hero and Dark. The Hero story followed Sonic, Tails, and Knuckles as they attempted to thwart Eggman’s latest plan to rule the world, while the Dark side followed Eggman’s story alongside those of two new companions: the Ultimate Lifeform Shadow the Hedgehog, and a double agent government spy named Rouge the Bat. Rouge has yet to appear in the live-action universe, but she acts as Knuckles’ rival and Shadow’s teammate in the video game continuity. Elements of her story in Sonic Adventure 2 still exist in Sonic 3, with the heist segment in the second act an obvious stand-in for her level Security Hall, but there’s no sign of the treasure hunter in the movie itself.

There have been reports that Paramount plans to give Shadow his own spin-off, and since Rouge didn’t show up in the movie based on her debut game, this would be the most logical place for her to appear next.

The Sonic movies have established that the speedy anthropomorphic animals saving the world are aliens from other planets. It was eventually revealed in Shadow the Hedgehog that Shadow has some alien DNA in him in the games, but he was initially presented as a creation made by humans when he debuted in Sonic Adventure 2. Sonic 3 fully commits to the alien backstory, revealing that he was found 50 years before the events of the film when a mysterious meteor landed on Earth. The GUN forces who investigated found Shadow inside and began running experiments on him in a hidden facility on Earth, rather than the Space Colony Ark orbiting the planet seen in the games.

Shadow’s backstory in the games is a bit more complicated, to the point where I’m not surprised they simplified it for the film’s shorter run time. In Sonic Adventure 2, Shadow is revealed as an invention by Gerald Robotnik, Eggman’s grandfather. The hedgehog was meant to be the Ultimate Lifeform, capable of unlocking the key to immortality. In Shadow the Hedgehog, it’s revealed that, in desperation, Gerald made a deal with an alien despot called Black Doom, who used his own DNA to help the professor finalize Shadow’s creation. In return for Black Doom’s help, Shadow would assist the Black Arms alien invaders take over the world. Shadow doesn’t know where he came from in Sonic 3, so it’s still possible that the Black Arms will play a role in a future film as his origins are revealed, but Gerald Robotnik didn’t create him in this continuity; he merely led the project that researched him after he fell to Earth.

In the games, Gerald was deeply invested in finding the key to immortality because his granddaughter, Maria Robotnik, had a terminal illness called Neuro-Immune Deficiency Syndrome. This led to the creation of Shadow and his prototype called the Biolizard, immortal creatures made with the hope that they could help facilitate similar breakthroughs for humanity. However, Maria seems to be a perfectly healthy kid in Sonic 3. I suppose, since Gerald isn’t creating Shadow in this timeline, there was no need to include her sickness as a motivator for his research. The sibling-like relationship between Maria and Shadow still hits many of the same notes, however. In both continuities, the two become inseparable friends that bond even as Shadow is being subject to experiments every day. Eventually, Maria’s death at the hands of GUN agents leads Shadow to try to destroy the world in both the games and the movies, but she lived her life as a healthy young girl in the films.

Though Maria does reach a tragic end in Sonic 3, her death is slightly different than it is in the source material. In most versions of the story, whether that be the games, anime, or comics, Maria is shot by GUN agents. In the live-action universe, Maria is nearly shot as she and Shadow attempt to make their escape after GUN shuts down the project and puts Shadow into stasis. However, the GUN agent that had her in his sights is interrupted by Commander Walters, who gets into a scrap with the shooter, leading to a shot being fired into a tank containing deposits of Shadow’s Chaos energy, setting off an explosion that results in Maria’s death. I imagine Paramount didn’t want to put a scene of a child being shot by the military in its widely distributed feature film, though elements of the original scene remain, as her death was still caused by GUN shutting down the project and attempting to eliminate loose ends.

Jim Carrey plays two Robotniks in Sonic 3. The eccentric mad scientist Ivo “Eggman” Robotnik who he’s played in every movie thus far, and his grandfather Gerald Robotnik. In Sonic Adventure 2, Gerald was long dead and had brainwashed Shadow to carry out his revenge-fueled plan to destroy the world in his absence. The movie version of Gerald is still alive, and able to manipulate Shadow and his grandson into doing his bidding. Eggman has gone his whole life without family, so he’s more than happy to help out his grandfather to make up for lost time, and Shadow’s grief for Maria is so strong, he’ll do anything if he’s told it will be in her honor.

Gerald dies at the end of the movie, though it’s in a much different way than he dies in the games. Eggman kills Gerald in a frankly anticlimactic fight inside the Eclipse Cannon space station, where in the games he’s killed by a firing squad after his descent into madness.

Rouge is one big character who doesn’t appear in the film’s main story, but there’s another key player who doesn’t show up when they do in the games: Amy Rose. The pink hammer-wielding hedgehog shows up in the post-credits scene, but in Sonic Adventure 2, she tagged along with Sonic’s crew, and was eventually the person who reminded Shadow of his true memories of Maria, rather than the distorted ones Gerald gave him to carry on his revenge plot. Since Amy’s not around and Shadow isn’t brainwashed, his turn from villain to hero comes from a different source: Sonic. After the two enter their super forms and beat each other senseless, Sonic comes to his senses and has a heart-to-heart with his rival about the futile nature of revenge, eventually reminding Shadow that even if Maria is gone, his love for her still lives on, leading to the sick as hell team-up as the hedgehogs save the day.

In Sonic Adventure 2, Eggman and Shadow use the Eclipse Cannon, a superweapon developed by Gerald Robotnik, to destroy part of the moon. This is meant as a show of power to make the people of Earth surrender to Eggman’s rule. In Sonic 3, however, our heroes divert its aim away from Earth, so instead of a direct hit on the moon, the cannon slices off the southern end. It looks like the world is just gonna let it stay that way, too, as you can see the severed section hanging out in the moon’s orbit in the post-credits scene.

In the final few minutes of the film, Sonic and Shadow team up, use the Master Emerald to take on their super forms, and save the world from cataclysmic destruction. This also occurs in Sonic Adventure 2, but while the movies have the two face an army of Gerald’s robots, the speedy hedgehogs fight something else as a final boss in the game. As a last-ditch effort to destroy the world, The Biolizard, the prototype for the Ultimate Lifeform, fuses with the Space Colony Ark and attempts to keep it on a collision course toward the planet. The Biolizard isn’t mentioned in the movie and seemingly doesn’t exist in the film universe, so while the final battle still has most of the elements that matter, our heroes are squarely focused on fighting Gerald in the climax.

After our heroes divert the Eclipse Cannon from Earth, the facility becomes unstable and self-destructs. To prevent the explosion from contaminating Earth’s atmosphere, Eggman and Shadow sacrifice themselves to move it away from the planet. Shadow was presumed dead at the end of Sonic Adventure 2, but was revealed to have survived in Sonic Heroes. Eggman, meanwhile, survives the events of the Dreamcast game and lives to bother Sonic and his friends another day. If Carrey’s version of the series villain is well and truly dead (there’s no tease of his survival like there was at the end of Sonic the Hedgehog 2), then that’ll be one of the biggest deviations Sonic 3 makes from the source material.

It’s still unclear how the movies will go on without him, but given the sendoff the character got, it would feel cheap to bring him back. We’ll know more when Sonic the Hedgehog 4 premieres in 2027.