- Green Hills, Montana is named for Green Hill Zone from Sonic the Hedgehog. Additionally, it could be named for the zone with the very same name, complete with the added 's' from Game Gear version of Sonic the Hedgehog 2.
- And on the topic of Sonic's grey sneakers, the shoes are wrapped with rags to hold them together, looking quite similar like Sonic's shoes in Sonic Boom.
- Robotnik noticeably wears armed sunglasses as opposed to the arm-less pince-nez sunglasses he's usually seen wearing in the games. He wears armed sunglasses in Sonic the Hedgehog (2006), however. After his normal sunglasses get bent from his encounter with Sonic, he switches to a pair of strapless goggles which combine the concepts of his armless sunglasses with the goggles he wears on his head but almost never puts over his eyes.
- Speaking of sunglasses, the ones Robotnik wears in this movie are square-shaped, a lot like the ones Warden Zobotnik (a character from the Archie comics, who is supposed to be an alternate universe version of Robotnik) wears
. - The headband that Sonic wears while using a pair of nun-chunks in the film has the same emblem from the title screens of the original Genesis titles and both Sonic CD, Sonic the Hedgehog 4, and Sonic Mania. It also references the Bonus Points from Sonic 1 and Sonic Lost World, as well as the items featured in the Adventure duology.
- Sonic playing baseball with himself in various roles during the film is reminiscent to two scenes:
- A bit in Sonic Underground where he goofs off by playing tennis against himself and acting as the umpire, before throwing a hammy John McEnroe-like tantrum and storming off the court in response to one of his own decisions.
- The episode "Unfair Ball" from Sonic X, where Sonic and friends played baseball for a Chaos Emerald wager against The Eggs: a team of specially-made baseball robots captained by Dr. Eggman himself.
- Early in the film, there's a brief first-person shot from Sonic's perspective as he runs through the forest to his cave. The shot is identical to the speeding first-person forest shots in the CGI intro to Sonic Adventure.
- During one of his speeding antics inside the motel in the film, Sonic could be seen doing his balancing pose, Sonic 1 style, with the animation itself looking more akin to Sonic CD and Sonic Mania's style.
- Sonic plays table tennis against himself, using a signboard that reads "Hill Top Rd." as the table.
- Sonic speeding along the Great Wall of China in the film brings to mind the Chun-Nan/Dragon Road Day stage of Sonic Unleashed. Robotnik pursuing him through here even echoes the sequence where one of Eggman's larger robots chases Sonic along the wall.
- During this chase, Sonic runs horizontally along the walls at one point. Running sideways along walls at high speed was a mechanic introduced in Sonic Adventure, which carried over to future games (most notably Sonic Unleashed and Sonic Generations, where it was prominent in some levels, but also in Sonic Lost World, where doing it at any time is part of the Parkour mechanic); a similar mechanic of running along steep inclined platforms was the precursor for this and was introduced in Sonic Chaos.
- The film shows Sonic running laps inside of a washing machine the same way a hamster would run inside of a hamster wheel. This doubles as a nod to an issue of Sonic the Comic, where Sonic runs on a generator wheel to test his speed and an accident with it ultimately gave him his famous blue fur, as well as for a Sonic Sez segment where Sonic warns Tails about the danger of climbing inside a washing machine after pulling him out.
- Sonic is seen wearing some worn-down shoes before trading them in for his iconic red shoes, also similar to the origin given by Sonic the Hedgehog Bible, Sonic the Hedgehog Promo Comic and subsequently Sonic the Comic.
- A Freeze-Frame Bonus in the baseball scene: Sonic's running animation when running at high speeds around the baseball diamond looks strikingly similar to Sonic CD's Pencil Test animation.
- Sonic using Rings as portals to go to different areas has been a mechanic since the very first game, where Giant Rings would take Sonic to the Special Stages.
- Their function is also similar to the warp rings in Sonic the Hedgehog (Archie Comics).
- When becoming a portal, Sonic's rings faintly make the iconic "Ring Loss" sound effect, and when entering/exiting them makes the even-more-iconic "Ring Pickup" sound.
- Save for one point in the second trailer; when Sonic is going through the Ring that brings him from his planet to Earth, the "Spin Charge" sound from the games plays when the Ring is shown opening up on Earth, rather than any type of Ring sound being used.
- The government is hunting Sonic down. This isn't the first time this has happened.
- It also isn't the first time that Sonic was transported from his world to Earth. In the movie, however, Sonic did so deliberately to escape from forces that have been chasing him down for his powers, whereas in the anime he, Eggman/Robotnik, and a few others were all sent to Earth by accident.
- South Island as it appears in the original Sonic The Hedgehog game is seen. We also see it at sunset.
- When Sonic blinks, one can notice that his upper eyelids are the same color as his fur, while his lower eyelids are the same color as his muzzle. This references how Sonic originally had flesh-colored eyelids that were later changed to fur-colored.
- On a similar note, when Sonic closes his eyes, one can see a line of small-but-present black eyelashes. He also had these in Sonic Adventure and Sonic X.
- For a moment, Sonic skates along the ground using two spinning metal discs. This is a reference to grinding, a mechanic first introduced in Sonic Adventure 2, with the spinning discs possibly representing Sonic Riders.
- The animation for him jumping on the discs strongly resembles his Spot Dodge animation from Super Smash Bros..
- At one point, Sonic jumps from Tom's truck and spins towards Robotnik's vehicle at high speed. Besides the obvious reference to the Spin Dash, this move looks exactly like the Drop Dash from Sonic Mania.
- When Sonic starts rolling along the ground, two sounds from the games play simultaneously: the iconic "Spin Attack" sound, and the "Dash Pad" sound.
- Robotnik being way slimmer than usual is actually a reference to Sonic the Hedgehog Bible, Sonic the Hedgehog Promo Comic and Sonic the Comic, where he starts out being on the thin side before gaining his iconic rotundness. He also had a slimmer design in Sonic the Hedgehog (2006) Not to mention Dr. Ivo Kintobor, the Mirror Universe counterpart of Dr. Robotnik from the pre-Super Genesis Wave continuity of the Archie Sonic the Hedgehog comic line (as of Sonic the Hedgehog issue #193).
- During the opening monologue of the first post-redesign trailer, the background music is a remix of Green Hill Zone.
- Some of the posters and renders of Sonic are shout-outs to the games:
- One pose from the first trailer's concept artwork has Sonic in his pose from Super Smash Bros. for Nintendo 3DS and Wii U. This was later recreated in the November 2019 motion poster.
- During the climactic chase through San Francisco, Sonic strikes a pose taken from his Super Smash Bros. Ultimate render.
- Another pose from the aforementioned concept artwork is him in a pose that looks similar to Sonic's pose from Sonic Mania's box art.
- Another pose from the concept art has the original design of Sonic in his pose from Sonic the Hedgehog (2006). This pose was later recreated with the redesigned Sonic and released as a standalone render when the second trailer was released.
- A poster that was released alongside the first trailer shows Sonic running along a large building in a city that looks very similar to Speed Highway. This comes up in the movie itself as Sonic races down the Transamerica Pyramid, resembling Speed Highway's "Going Down" portion, complete with Robotnik drones in hot pursuit.
- The poster released alongside the second trailer has Sonic in his pose from Sonic Unleashed's box art.
- Sonic is shown sliding underneath a vehicle at one point to escape weapon fire from Robotnik. His pose while sliding looks identical to both the sliding part of his somersault animation from the Sonic Advance games and his sliding animation from the modern games, particularly Sonic Unleashed, Sonic Colors, and Sonic Generations.
- Robotnik's machines have a sleek white aesthetic, which brings to mind his robots from Sonic the Hedgehog (2006), the Meteotech security robots made by his legitimate security company in Sonic Riders, and the Sonic Forces incarnations of the Egg Pawns. The first form of the persistent truck drone he sends after Sonic is somewhat similar to a vehicle from SegaSonic the Hedgehog that ends up capturing Sonic in that game's intro.
- A Freeze-Frame Bonus includes a row of switches with a handwritten BADNIKS label as Robotnik restores power to his mobile lab after a surge.
- Sonic's reddish-brown pouch, which is slung around his torso, and contains his rings collection. This is similar to Sonic the Hedgehog (SatAM), where Sonic would wear a red backpack that he hid Rings inside of.
- He also packs up and wears a red backpack when he plans on running away from his hideout.
- Sonic is shown to be given his iconic shoes by Tom and Maddie's niece. This is a call-back to the Sonic the Hedgehog Bible, Sonic the Hedgehog Promo Comic and Sonic the Comic, where Robotnik (as Kintobor) gives Sonic (who had been wearing trainers) his well-known red shoes.
- This film’s version of South Island bares some resemblance to its appearance in the 8-Bit version of Sonic 1; in particular, a map of the worlds that Longclaw hands to Sonic includes a faithful picture of South Island itself representing Sonic's former home. That same map also has symbols referencing the Sega Saturn, the chequered planet used for the Blue Spheres Special Stage, and the stylized sun from a loop-de-loop in early concept art for the first game.
- When Sonic zooms by Green Hill Zone some of the terrain crumbles referencing the games Temporary Platform.
- One section looks a lot like a section of the Green Hill Zone in Sonic Generations.
- Also, some of the textures are taken from Labyrinth Zone.
- Baby Sonic himself looks a lot more like Classic Sonic, with his size and proportions putting the shrink ray from Sonic CD in mind. It's also not the first time we get to see a child Sonic in a non-game format.
- The music from the scene is mostly the opening to Sonic Mania.
- This film’s version of South Island
- The locations Sonic visits in the New Year 2020 trailer contain multiple:
- Sydney, Australia - This is a reference to Sonic: Live in Sydney.
- Tokyo, Japan - SEGA is headquartered in Tokyo.
- New York City, New York - Station Square from Sonic Adventure and Empire City from Sonic Unleashed are heavily based on New York.
- San Francisco, California - The city and highway-based levels in Sonic Adventure 2, most famously City Escape, are based on San Francisco, due to SEGA of America being headquartered there (which also served as the inspiration for Crazy Taxi).
- Robotnik's red bodysuit and goggles◊ bears a strong resemblance to what he wears in this piece of concept art for Sonic Adventure.
- "Speed Me Up", the movie’s theme song, contains several: The opening beats are taken from Metropolis Zone. The lyrics also name drops “Knuckles” and “Tails”, a nod to Sonic’s fellow allies in the games (with Tails eventually making an appearance in The Stinger — not long after the portion of the song that mentions him plays in the credits, even).
- The Knuckles Tribe hunts Sonic in the first part of the film. The leader of the group is Pachamac, from Sonic Adventure, who's mask in the movie resembles the original design's facial markings.
- During the sequence where Sonic rushes around his cave, there's a segment dedicated to him playing the guitar, Which brings Sonic the Hedgehog (SatAM), Sonic the Hedgehog (Archie Comics) and Sonic Underground to mind.
- Crazy Carl is the only citizen of Green Hill, Montana that knows Sonic exists and has a drawing of him that looks like Sanic Hegehog, an infamous piece of Sonic fanart that was later featured as DLC in Sonic Forces.
- After disabling one of Robotnik's machines with his own body during the high-speed chase on the highway, Sonic groggily says something that, unless one had played the games, would normally be considered a Waking Non Sequitur:Sonic: Ooouugh... GuEsS I hAd a BoNus LiFe...
- One of the symbols on the planet map that Sonic owns is the logo for the Sega Saturn and of the Master Emerald. The map itself is based on concept art◊ of the original Sonic the Hedgehog. Underneath the Master Emerald, is the same unknown language that appears in on the buildings in Sonic Forces.
- Sonic's pose during the scene where dozens of missiles are shooting at him is a reference to one of his idle animations from Sonic the Hedgehog 2.
- Sonic loses his rings in ways that parallel the video games:
- The first time, albeit less like the games, is when Tom shoots him with the tranquilizer dart, which knocks Sonic out, makes him drop the Portal Ring he's holding, and, because he saw Tom's San Francisco shirt in his delirium, accidentally sends his bag-of-rings to the Transamerica Pyramid in San Francisco.
- The second time, Sonic hits a tree after losing control from running down the Pyramid, where the rings fall out of his satchel and scatter on the ground, much more in line with how he loses them in the video games, when he's hit by an enemy.
- Finally, during his first encounter with Robotnik's prototype vehicle, he hits the ground before the rings scatter around him.
- Sonic, of course, defeats Robotnik at the climax of the movie by hitting his ship over and over, like he does in any of the games.
- The way he does so with a series of rapid attacks after building up energy is also reminiscent of the Light Speed Attack. In addition, the camera cuts repeatedly between Sonic and Robotnik to emphasize the first eight hits of the assault. In most 2D Sonic games, it takes eight hits to destroy the doctor's machines.
- In most Genesis games, Eggman goes down after 8 hits and most gamers counted them aloud while fighting him in order to not lose count. During the movie, many theaters had the public counting aloud, too!
- The Creative Closing Credits recap the movie and look just like sprites from the original 16-bit Sonic games.
- Both the Sonic 2 halfpipe and Sonic 3 & Knuckles Blue Sphere special stages get scenes in the credits, with edits to reference parts of the movie.
- Despite Spikes of Doom not appearing at all in the movie, one scene in the credits has a room full of them.
- Towards the end of the credits, Robotnik's jet from the climax of the movie appears, but with the wrecking ball from the first boss in the first Sonic the Hedgehog attached to it.
- The shot where Jim Carrey's name comes up also has a background full of screens flashing the Eggman emblem as seen from Sonic Adventure and onwards. Their arrangement, and the way they flash, resemble the screens in the background of the Phantom Egg fight in Sonic Mania.
- Sonic refers to himself and Tom as, "a couple of loose cannons, living by their own rules", a possible reference to Sonic's image songs in SA1 and SA2.
- When the credits recap the chase scene from the climax, the palette used for Paris makes it bear a resemblance to Spring Yard Zone, an urban level from the first game.
- In the motel scene, when Sonic farts, Tom asks him what he ate. His answer is "something called a chili dog."
- Inspired by the ovular white aesthetic of Robotnik's drones, Sonic starts mockingly calling him "Eggman". Robotnik also alludes to this earlier in the movie with his allegory about pulling stuff out of his eggsac. In the novelization, Sonic instead calls him "Robuttnik".
- The white egg shape drones could be seen as a reference to Sonic the Comic Robotnik's white egg shaped Egg-Cam drones.
- The Mushroom Planet brings Mushroom Hill Zone to mind, but due to Sonic's profound dislike of mushrooms in this movie, it could also be seen as a sly Take That! to the Mushroom Kingdom. This was confirmed by writer Patrick Casey to be intentional.
- Not only is Robotnik beginning to look more like the Eggman of the video games when he's trapped on the Mushroom Planet, he even starts to speak in a more gravelly voice very similar to Mike Pollock's take on the character and imitates his famous laugh too.
- Also noteworthy is Robotnik's movements during the last minutes of his screentime resembles the way his Death Egg Robot moves in general.
- Robotnik rigs up Sonic's shed quill as a power source by placing it inside a glass tube capped with metal on each end. While the game might not have included a blue variant, those who spent enough time raising their Chao might recognize this item as a Chaos Drive, which was used by both G.U.N. and Gerald Robotnik to power their creations.
- When Tom and Maddie show Sonic that they converted the attic into a room for him to stay in, his bed is designed like a race car which he likewise had in Sonic the Hedgehog (Archie Comics) in his home in Knothole. The bed's colour scheme, particularly the wheel's star-shaped hubcap, also make it resemble a checkpoint.
- When Dr. Robotnik is pulling up his evil playlist, a Freeze-Frame Bonus shows he also has a playlist of songs by Crush 40, the band who has made several main themes of the series.
- During the bar fight, Sonic can be seen shoveling chili dogs down his throat.
- After Sonic and Tom run out of the Piston Pit, Sonic asks if they forgot to tip. He then follows up with this: IT DOESN'T MATTER! This is the name of Sonic's main theme song in SA1 and SA2.
- During the chase sequence, the camera perfectly mimics the ending shot of the San Francisco stage of Sonic Adventure 2.
- Just before the credits, the film flashily animates the title logo, not unlike what the Sonic OVA did at the conclusion before its own credits.
- Longclaw's relationship with Sonic in the film may be a reference to Stay Sonic (a guidebook to the world of Sonic the Hedgehog published in the United Kingdom in 1993 by Fantail), in which Sonic was stated to be found by an owl named Sophocles. Her design is also a reference to the bird-like murals seen in the first games' Labyrinth Zone and Sonic The Hedgehog 2's Aquatic Ruin Zone.
- Sonic's title the Blue Devil is shared with the name of Metal Sonic's kart in Sonic Drift 2.
- In a Freeze-Frame Bonus, one of the streets of San Francisco is named Mega Drive* .
- When Tom and Maddie are fixing their house, you hear a piano rendition of the Green Hill Zone theme.
- The military's Olive Garden bribe and the general wanting to speak with Sonic might be an obscure reference to Shadow the Hedgehog, where in expert mode the Commander invites Shadow to talk.
- On that note, there's a popular Mondegreen about the White Jungle stage's music from Sonic Adventure 2 that turns the line "Oh yeah, hurry through the unexplored land" into "Oh yeah, hurry to the Olive Garden".
- Sonic's supercharged power manifesting whenever he gets emotional is very much a perfect representation of Tikal's quote about Chaos Power "being enriched by the Heart" in Sonic Adventure.
- There's plenty of references within Sonic's bucket list itself; such as: find a genie lamp, compete in a sport, learn parkour, sing a national anthem, guitar solo, sail the high seas, and run along the Great Wall, the last of which ends up happening in the film's climax.
- The emblem of the police department in Green Hills, and the corresponding badges the officers have, closely resemble a seven-petaled version of a Green Hill Zone sunflower.
- Sonic's final movie design has a small strip of white fur above his nose, which creates a visual of his "one eye with two pupils" design of the games, despite him having two separate eyes in the film design.
- The final battle with Robotnik is in fact a straight recreation of a boss fight from the games, with Robotnik piloting a deadly machine, and Sonic defeating him by repeatedly leaping and striking the craft with spinball attacks until it is disabled.
- The Sonic the Hedgehog: The Movie OVA from 1996 also started with Sonic interacting with an elderly owl character on his island home and included a joke sequence focusing on a turtle being slow.
- After saving Sonic from the pool in the first episode of Sonic X, Chris told his parents that he rescued a cat, much to the latter's annoyance. Guess what Sonic does in the movie when he's spotted by Tom for the first time? He actually meows like a cat.
- A possible one during the car chase scene, when the tiny badnik is cutting Tom's car in half, Sonic asks if Tom has car insurance. This may be a reference to Sonic's cameo in a Progressive insurance commercial.
- In the alternate origin, Excalibur and the training sword can be seen.
- In the novelization, Sonic's powers are explicitly identified as "Chaos Energy". The way Tikal describes Chaos Energy in Sonic Adventure also reflects how Sonic's energy works in the movie. And, just like in Adventure, the Knuckles Tribe wants to harness the energy.
- At one point Sonic is show reading a bunch of The Flash comics. In Sonic the Hedgehog (Archie Comics), Sonic was repeatedly shown to be a comic book fan, even in Issue #82 comparing the experience of running across the rooftops of Station Square to being like the fictional superheroes The Dark Bat (Batman), The Super Surfer (Silver Surfer), and The Rush (The Flash).
- In the Zillow scene, the property owner's name is Amy Rose.
- Sonic loving Keanu Reeves and thinking he's a national treasure is a potential reference to the old joke poster◊ for a Sonic the Hedgehog movie where the various animal characters are just various actors in normal clothing under a colored lighting filter, with Keanu naturally playing(?) the role of Sonic.
- Another interesting reference to Keanu is a shout-out to the directors of The Matrix. What is the name of Tom's family? The Wachowskis.
- The basketball game Sonic and Tom play at the bar is the same type used for the Sonic Sports Basketball arcade games, although with generic branding.
- Debatable on how intentional, but early in the film when Sonic is playing ping pong by himself in his cave, he trips and drops his bag of rings. He reacts with a small "Oh no" in an almost identical tone to his and Knuckles' pain sounds in Sonic Adventure.
- During Sonic's childhood flashback, he picks a flower for Longclaw, which turns out to be a sunflower in the exact shape from the original Green Hill Zone's scenery.
