"Double the speed, double the fun! Celebrate 20 years of Sonic with Sonic Generations."
Sonic Generations is a main series title in the Sonic franchise, released in 2011 for the PlayStation 3, Xbox 360, the PC (via Steam) and the Nintendo 3DS to commemorate Sonic's 20th Anniversary. The 360/PS3/PC versions of the game utilizes both 2.5D (mostly in the "Classic Sonic" sections) and a mix of 2.5D and 3D gameplay in the style of Sonic Colors Wii and Sonic Unleashed HD's daytime stages (in the "Modern Sonic" sections), while the 3DS version's "Modern Sonic" levels are stylistically similar to the Sonic Rush series and Sonic Colors DS. Both HD console versions and the 3DS version support stereoscopic 3D, though gamers without a 3D TV aren't required to use one to play the HD console versions as they can be played on any TV and the stereoscopic 3D on the 3DS version is not required to play the game properly and can be turned off, as it is typically used for visual effects on that version.The story is that Modern Sonic and his friends are celebrating his birthday when a mysterious new enemy named 'Time Eater' crashes the party and sends them back to the past where Sonic meets his younger self, Classic Sonic. They both discover the world is losing its color, their friendshave been petrified and the timeline has been disturbed. Both Modern and Classic must team up to stop this mysterious enemy, rescue their friends, restore color to the world, and fix the timeline.Their journey takes them through three eras: Classic, Dreamcast, and Modern. The 3DS and console versions have different levels, and share only the famous Green Hill Zone from Sonic 1.The stages are:
Sonic Unleashed: Rooftop Run* Spagonia with a festival theme. Contrary to common belief, Flying Battery is not featured., Eggmanland* The setting for the fight against a completed version of the Egg Dragoon (Last Boss against Dr. Eggman in Sonic Unleashed).
2ĹD: Used to varying degrees. Classic Sonic's gameplay focus remains strictly on a 2D plane in a 3D environment, while Modern Sonic's gameplay uses the same formula used for Sonic Colors and Sonic Unleashed's Daytime stages. The 3DS version is entirely in 2.5D, but with the Sonic Rush feel for Modern and a platforming-focused feel of the Genesis games for Classic.
Action Commands: By jumping off of certain ramps or through rainbow rings, Modern Sonic can perform tricks when you press in different directions. These are also used to dodge the orca's attacks in Modern Sonic's portion of Emerald Coast in the 3DS version.
And I Must Scream: It's heavily implied that Sonic's friends are still self aware while petrified.
In the epilogue, two different time-period versions of Robotnik are stuck in a state of absolute nothing for what appears to be a long, long time.
Art Evolution: Perfect Chaos has undergone a considerable redesign, looking much different than his original form. A comparison between the original and redesign can be seen here◊ and here.◊
Apparently, this was how he was originally intended to look; however, due to technological limitations, they were unable to do it, resulting in the Chaos from Sonic Adventure. (The version seen in Sonic Generations does resemble the Perfect Chaos seen in the intro cinematic for Sonic Adventure and its DX counterparts.)
Ascended Meme: A subtle one: Shadow has that DAMN fourth Chaos Emerald as a reward for his rival fight in the HD version. (His rival fight just unlocks the boss in the 3DS version, as Chaos Emeralds are gained through Special Stages in it.)
Attack of the 50-Foot Whatever: Giant-sized Badniks appear in a mission in Green Hill. They're immune to any damage Sonic does, and are mostly used as bouncing platforms.
Super Sonic loses rings at a faster rate than usual. The modern version can now fly through levels in a manner similar to the Chaos Control ability in Shadow the Hedgehog. Unfortunately, doing so drains rings ridiculously fast, limiting its usefulness. Classic Super Sonic is also not that much faster (if any faster at all) than Modern Sonic.
This ability gets a temporary upgrade to Difficult, But Awesome in Seaside Hill. In most zones, the course is surrounded by pitfalls, but the course in this zone is surrounded by water, which Sonic can run across by boosting. This allows the player to do some major sequence breaking. See here.
It is also generally used by speedrunners that have managed to learn how to use the Boost to swiftly get through stages without being harmed.
Baby Talk: Very slightly with Classic Tails in the HD version, who has an adorable lisp and says "w-" when he means to say "r-" occasionally. Also applies for the other language settings.
Bad Ass: Both Sonics, but mainly Modern (as the end of the Egg Dragoon boss fight in the HD version will tell you).
Bonus Feature Failure: The ability to name your skill sets in the HD version for easy identification is a good idea in theory. But here, you cannot use the PS3 or XBox360's keyboard feature and must instead choose two terms from a long, unalphabetized list. That in itself would not be unbearable, but after choosing two terms, they are automatically separated by an ampersand, unless the first term is "Skill Set" and/or the second term is a letter (the default naming scheme). Nearly every catchy title you can think of for your Skill Sets will be blemished by that obtrusive "&". Even PC gamers are stuck with this.
Book Ends: The game begins and ends at Sonic's party.
Border Patrol: Modern Sonic can run across the surface of Seaside Hill's ocean in the HD version, but if he runs too far off the main path for a couple seconds, the giant Chopper from Green Hill leaps from the water to snap him up.
The platforms that fly when Classic Sonic runs on them in Sky Sanctuary Zone are based on the spinning blue tops of Marble Garden Zone. The twist, however, is that these platforms are temporary and wear out after enough running.
Every nation from Unleashed has their flags flying in front of Spagonia University (which both Sonics pass by) at the beginning of Classic Rooftop Run in the HD version.
In the HD version, Modern Sonic can ride around Seaside Hill in a go-kart, itself a nod to the bobsled in the original Seaside Hill and Bullet Station.
Perhaps the biggest - The game starts the exact same way as the original: Green Hill Act 1, with the level even starting the same way the original level did.
If you hit the ship in Modern Rooftop Run with enough robots, it will drop rings, like the bosses in Sonic Colors did.
The original Sonic the Hedgehog is playable in the console version.note The PC port removed it, however. Unlocking it is a simple matter of getting the Sega Genesis controller from the Skill Shop.
A Planet Wisp mission has the spikeball see-saws from the first game's Star Light Zone. There's another such mission in classic City Escape.
Two missions in Crisis City and Planet Wisp have you bouncing the goal post all the way to the goal, like you could in Sonic 3 & Knuckles.
Call Forward: Classic Sonic has several Skills that reference the abilities and shields he can use past the original game. One of his last Skills is the Homing Attack, a move that Modern Sonic can already use naturally.
In the 3DS version, Classic Sonic learns the Homing Attack (from himself) earlier, at the start of the Modern Era. At the end of the game, he instead learns how to use Modern Sonic's Sonic Boost, although the ability is unusable as a Skill.
CamelCase: Sonic the Hedgehog CD's Japanese soundtrack's music for the present time period of Palmtree Panic can be unlocked and the song has the title capitalized as "PalmTree Panic."
The Cameo: City Escape in the HD version is packed to brim with them. The names of some modern characters appear on a Chao in Space 2 ad. Some older faces, like Bark, Bean, and Fang, appear on wanted posters. Even Mighty and Ray can be spotted (on "Missing since 1993" posters, no less).
Orbot and Cubot appear in Eggman's flashback to The Stinger of Sonic Colors, which also explains why they are otherwise absent from Generations.
Omega gets another cameo in Speed Highway, as one of the roads is 123 Omega Road. 123 is his number in the "E" Series.
Look carefully at the beginning of both stages of Planet Wisp and you'll see some White Wisps. There's even one in Classic Planet Wisp who dances exactly like Yacker does in the Loading Screens of Colors!
Captain Obvious: Of a peculiar kind. During the fight against the Time Eater in the HD version, a lot of Sonic's friends kindfully remind you "That looks like a homing shot," but only Shadow says "That's a homing shot" with certainty.
Cardiovascular Love: Rouge's challenges in the HD version require using her charm attack, which consists of her blowing heart symbols at Egg Pawns to make them lower their guard.
Casino Park: Casino Night Zone, in both versions (though it's only a proper level in the 3DS version).
Chainsaw Good: The GUN truck, which comes equipped with three giant buzz saws this time around in the HD version's Modern Sonic portion.
Chekhov's Gag: The signpost from Classic Crisis City passes by in the foreground a little while after it's first blown away.
Chekhov's Gun: There's some effort hiding Dr. Eggman from the player on the Death Egg Robot boss in the HD version and the Big Arm boss in the 3DS version, especially when he's "kidnapped" by Time Eater...
Completely Different Title, The Foreign Subtitle: In Japan, the 360/PS3 versions of the game are titled Sonic Generations: White Time and Space, while the 3DS version is titled Sonic Generations: Blue Adventure. In western territories, all versions of the game are simply titled Sonic Generations. Even so, both versions have a white or blue backdrop on the boxart.
Continuity Nod: Being a game all about Sonic's history, there are loads of it. Now has its own page.
Continuity Porn: The entire game is this as it features levels from just about every major Sonic game in the series as well as games not in the major series, including the beloved Sonic CD.
Even moreso considering the nature of the game as a sequel to the events of Colors; direct continuity is something rarely seen in more recent Sonic titles, so having it established and directly referred to in a game all about Sonic's history is a notable achievement on Sonic Team's part.
The preferred name or moniker for Dr. Ivo "Eggman" Robotnik can be thrown into confusion when Classic Eggman states no one calls him by his real name anymore. In as early in modern (western) continuity as Sonic Adventure, Eggman and Sonic use the Robotnik name, still preferring his real name in that time, Sonic using both.
Cool Board: Classic Sonic has a skateboard, in true early 90's fashion. Modern Sonic uses a snowboard in City Escape, just like old times, as well as in a mission in Rooftop Run.
Also, the ability to use a skateboard at will is one of the unlockable skills for Classic Sonic.
Crisis Crossover: The current, green-eyed Sonic meeting his retro, black-eyed self through Time Eater's disturbance of the time holes. Both hedgehogs must team up to fix Sonic's timeline and defeat the Time Eater.
Damn You, Muscle Memory: If you're used to the Homing Attack on the HD versions of Sonic Unleashed* where it was shared with the 'Boost' button (X on 360 and Square on PS3)., you may have to readjust yourself to the standard Homing Attack controls used in all the other Sonic games for Generations HD* Pressing the 'Jump' button (A on 360, X on PS3) in mid-air to perform it..
There's also the issue of trying to do a Homing Attack as Classic Sonic and trying to do a Spin Dash as Modern Sonic.
Anyone who was used to playing Colors on the Wii's Classic Controller may have difficulty pressing the slide/stomp button without instinctively reaching for the Y/Triangle button.
The double-jump in Colors isn't present in Generations (double-tapping the jump button as Modern Sonic does the forward-air-dash move), which can seriously screw the player up when they accidentally try to double-jump up to a higher platform.
Death Throws: When you lose a life as Classic Sonic, aside from bottomless pits.
Deflector Shields: The Flame, Aqua, and Thunder shields return from Sonic 3 in certain missions, and can be equipped in any main level once said missions are completed. The bounce, flame dash, and spark jump capabilities are fully intact.
Department of Redundancy Department: In a cutscene after Chemical Plant in the HD version, Modern Sonic says that he's getting "deja vu all over again," paraphrasing a famous quote from Yogi Berra.
In the Modern Era, the challenge stages take a MASSIVE difficulty spike, especially the Doppelganger races which now leave extremely little room for error.
Divergent Zone Evolution: As Green Hill Zone has been brought back, Seaside Hill has understandably taken many liberties to differentiate itself from the zone it was originally supposed to be a throwback to. Most notably, it's incorporated some aspects of Ocean Palace from Heroes as well as added a water section.
Alot of the other zones got upgrades to their unique features and obstacles. City Escape's skateboard section was lengthened and expanded as well as the truck was given an upgrade so it will be less like Speed Highway.
Double Jump: Classic Sonic can do one with the Thunder Shield.
Double Unlock: Many skills require you to first complete a specific challenge, then buy it from the store.
Do Well, But Not Perfect: Some of the Red Star Rings require you to take a lower path, going against regular Sonic logic to always take the highest path
Epic Fail: At the end, not only is Modern Eggman stranded in an infinite space void of time with Classic Eggman, but he accidentally convinces Classic Eggman to give up on villainy entirely and pursue a career in schoolteaching. Odd enough, Eggman approves.
Modern Eggman: That's not a bad idea! I've always enjoyed telling people what to do!
Eternal Engine: Chemical Plant. Planet Wisp is also well on its way, as it's being constructed on an idyllic alien planet.
As well as Eggmanland, which serves as the the battle arena against the Egg Dragoon.
Evil Laugh: Lampshaded by Classic Eggman as Modern Eggman laughs hysterically.
Classic Eggman: Wow. Will I really get that crazy?
Excuse Plot: A giant monster has caused Sonic's friends to become lost in time, and Sonic has to team up with his past self to race through locales from his earlier adventures in order to save them! Sounds good to me!
Failure Is the Only Option: After the ending credits, Classic Eggman finds out that Modern Eggman has never beaten Sonic. He gets discouraged by this and decides to go get his teaching degree. Modern Eggman thinks that's not a bad idea since he enjoys telling people what to do.
Final Boss: Hedgehog rivals aside, the boss fights are all final/true final boss fights from other Sonic games; the Time Eater is their successor for this game. The only exception to this is the Egg Dragoon (which was only the penultimate boss in Sonic Unleashed, although it did serve as the Werehog's Final Boss); it should also be noted that Shadow served as the Final Boss in Sonic Adventure 2's Hero Side story.
The Time Eater also fires lasers in the final battle.
Flanderization: The truck in City Escape. Although in Sonic Adventure 2, the main purpose of the truck was probably to catch Sonic despite collateral damage. In Generations, it basically wants to kill and maim Sonic without any care for its surroundings (Because why on earth would a truck need three buzzsaws, rocket jets, and the ability to drive on the side of a freaking building?).
Compared to Eggman's begging for help when he's captured after the Death Egg fight, Eggman has no objections when the Time Eater grabs him after the Egg Dragoon battle and it takes place in a fraction of the time as the first. With the revelation that the Time Eater is controlled by the two Eggman, one can see that the first fight was delibarately thrown and that the second was actually a rescue.
Friendly Enemy: Silver. He treats his Arena Battle with Sonic as a sparring session and seems to have a lot of fun whether he wins or loses.
In the PC version, it is literally impossible to play the game with most non-Xbox 360 gamepads. Due to a different input format between the 360 controller and other PC controllers, the game will interpret a non-360 controller as having random buttons fired at intervals, making Modern Sonic randomly quick-step left and right and cutscenes skip themselves (the game thinks that the player has pressed Start repeatedly when they haven't). The quick-stepping bug actually renders Seaside Hill Act 2 Un Winnable with a non-360 gamepad unless you hammer the boost button and get lucky.
The PC version has a couple of consistently-crash-causing spots. The most notable is Rouge the Bat's challenge for Modern Sonic in Seaside Hill, which has a very high chance to crash to desktop at any point during the stage.
Trying to access the online "Challenge Mode" can be an exercise in frustration, as something about the game's communication with the leaderboard data servers (which takes place every time the menu cursor is moved) causes it to almost always dump the user to the desktop with an error message when it tries to load record data.
Heroic Mime: Classic Sonic. The 3DS game, which has text boxes to make up for having less voice acting, only has punctuation like "?," "!," and "..." similar to the main characters of Nintendo and Camelot's Golden Sun series.
Hoist by His Own Petard: Silver ultimately loses his rival battle by being crushed by the gigantic ball of debris that he tried to attack Sonic with.
Hub Level/Playable Menu: The 360/PS3 version skirts the line by having one big 2.5DWhite Void Room Hub that serves as an "interactive menu" for selecting levels/bosses, talking to Sonic's friends, accessing extra content, etc. Within the narrative, Tails explains that said void is where the stages end up falling into after the Time Eater distorts their position in time and space.
Modern Sonic's animations are from Unleashed and Colors, plus a unique idle animation if he's standing in water.
I Got Bigger: Classic Sonic and Tails are Modern Sonic and Tails as young children.
Indy Escape: Both acts of City Escape, and other levels.
Internal Homage: Tons of them. Rooftop Run (originally from Sonic Unleashed) has zipline platforms like in Sonic 2's Hilltop Zone and dropping platforms with spikes on them like in the original game's Marble Zone.
And the Classic level ends with what appears to be Sonic & Knuckles' Flying Battery, complete with Eggman logo.
Limited Special Collector's Ultimate Edition: The "Collector's Edition" for the 360/PS3 versions of the game comes with a statue featuring both Modern and Classic Sonic, a commemorative Gold Ring, the "20 Years of Sonic Art" book* Featuring never before seen artwork., the "20th Anniversary Sonic Soundtrack"* Featuring a selection of tracks handpicked by Sonic Team., the "History of Sonic: Birth of an Icon" documentary* An exclusive collection of interviews and footage charting Sonicís life from inception through to becoming one of the most iconic characters in videogame history., and Downloadable Content* The Casino Night Zone Pinball Minigame, a 20th Anniversary theme, and a Super Sonic costume for your Xbox 360 Avatar.. Only available in Europe and Australia though.
The Japanese-exclusive "Special Editon" comes with a crystal cube featuring Modern Sonic with the Classic Sonic TV as the indentation.
Literal Ass Kicking: How Classic Sonic deals damage to the Death Egg Robot boss in the HD version in the first phase of the battle.
Loads and Loads of Characters: Though only Classic and Modern Sonic are playable, a majority of his friends do show up as non-playable characters.
Mercy Mode: The Nintendo 3DS version of the game's Time Attack mode and the Challenges in the other versions counts as this. Previous handheldSonicgames' time attacks sent you straight to the "retry/change-zone/change-character/quit" menu after either finishing the level or dying, but in Generations this happens only after having completed the stage; dying results in either restarting the stage or respawning at the last checkpoint instead. This means you can practice sections as much as you please. However, respawning at a checkpoint doesn't set the timer to whatever time you happened to run past said checkpoint. So, if scoring a perfect time is your top priority, you have to restart the level manually.
Neither Kele Okereke or My Chemical Romance are heard anywhere in the game.
Mission Control: Omochao, to some extent. All of Sonic's friends join in as well in the final boss battle, calling out incoming attacks. Might qualify as a case of Stop Helping Me!.
Monster of the Week: A tradition since Sonic Adventure, Time Eater is the one for this game. Subverted: it was a monster but it's turned into a manned robot by Dr. Eggman with the help of his past self.
Classic "Escape from the City" has a brief remix of Endless Mine, from Sonic 3 and the melody of the City Escape trial version.
Modern's version of "Escape from the City" uses pieces of the theme for the Snowboard Race multiplayer level and "It Doesn't Matter" from Sonic Adventure 2.
An entire section of Modern Seaside Hill is practically devoted to remastering Ocean Palace. That's right, they haven't just subliminally seduced you with the use of putting traits from older Sonic series selections into newer songs, but they mashed-up two themes from Zones of the same category!
In one section of classic Chemical Plant, Sonic hits a spring and goes so fast he outruns the camera, this is a glitch that could only be done in Sonic 2, and can't be done in any other stage in Generations
The opening to Sonic and Shadow's rival battle is exactly like the opening to Sonic Adventure 2: Battle.
While said rival battle takes place outside the space colony ARK, the SA2 opening is actually set in Radical Highway instead. That level in question marks Shadow's first playable appearance in the whole series, so, if you also consider that Shadow and Sonic never actually faced each other in Radical Highway, the re-use of the level in the 3DS version of Generations for the rival battle due to technical constraints suddenly becomes more justifiable.
There are a few grape vines in Sky Sanctuary's hub. According to the Sonic 3 manual, these were Knuckles' Trademark Favorite Food.
In Mushroom Hill Act 1, there's a checkpoint just before the goal. This is a subtle nod to the mini-boss fights in Sonic & Knuckles.
Nerf: In the console and PC version, the Sonic Boost's ring-attracting effect has been reduced from Unleashed and Colors.
Never Trust a Trailer: Apart from the launch trailer, none of the CGI shown in the trailers exists in the game, infact the trailer at the start is the only cutscene to use CGI, the rest use gameplay models.
Never Say "Die": Dr. Eggman says how he is going to turn Sonic into blue jelly.
When Sonic sees himself in a mirror, Dr. Eggman says he better get a good look, because it's the last thing he will see before Eggman "closes his eyes forever."
No Death Run: Completing an act without losing any lives gives you a Perfect Bonus, which boosts your rank by one full letter grade. In the main levels, the coveted S rank is only attainable by giving an A-rank performance with no deaths.
Restarting an act lets you try for the Perfect Bonus again, at the cost of a life* alternatively, you can quit to the level select and re-enter, saving you a life, but subjecting you to extra loading time. Strangely, dying before reaching your first checkpoint eats up one life and sets the clock back to 0:00:00, as if you had restarted the act, but the Perfect Bonus is no longer attainable* this can thankfully be circumvented by restarting the act before the loading screen pops up.
It's possible to earn S-ranks in the challenge levels even if you lose a life, as completion time is the only deciding factor. But since dying will usually set you back a considerable amount of time, a No Death Run is still recommended.
Nostalgia Level: Every level in the game is derived from old Sonic games, though the level design is mostly new. It works both ways; Modern Sonic plays through classic stages with the new style of gameplay, and Classic Sonic plays through newer stages with nostalgic gameplay.
Not Bad: Knuckles says this to Sonic after he defeats the Time Eater.
Not so Fast, Bucko!: In Act 1 of Crisis City in the HD version, as you approach the goal sign, it gets carried away by a flaming tornado.
Odd Man Out: Generations can be considered this, as it's the only 3D Sonic game to not have a vocal theme.
Oh Crap: Classic Sonic has no dialogue, but his expression at the Time Eater's initial appearance is definitely this.
Oxygenated Underwater Bubbles: Chemical Plant's Mega Mack features these, unlike the original level. Seaside Hill also has them, which is, again, a new thing as Seaside Hill's original iteration had no underwater gameplay.
The Red Burst Wisps return in Tropical Resort in the 3DS version.
The Fire Shield power-up from Sonic 3 finally makes a return. It still allows Sonic to perform a fire tackle.
Iblis' minions return in Crisis City.
Pop Star Composer: Alex Makhlouf, of Cash Cash, does a few remixes for the game.* If you really want to know the specific remixes he did, according to the OST's booklet they are: Classic Speed Highway, "Going Down!?", Classic City Escape, "Super Sonic Racing" and US Stardust Speedway for the console version; Classic Radical Highway, Modern "Back 2 Back" (Water Palace), Big Arms and the Special Stages for the 3DS version. Tony Harnell and Ted Poley also returned to sing "Escape from the City".
Pre-Order Bonus: Preorders from GameStop in the US or GAME in the UK net you the Casino Night DLC minigame. On the other side of the pond, Japanese preorders come one of two bonus soundtrack CDs (depending on the ordered version) containing the original songs of just about every first stage in the franchise.
The GameStop Xbox 360 pre-orders also come with an avatar outfit of Super Sonic and a 20th Anniversary background theme.
Scenery Gorn: Crisis City, and the ruined Station Square in which you fight Perfect Chaos.
Sega Hard: The Doppelganger Races. Good. God. The premise is simple enough: run through Act 1 or 2 of a zone and reach the finish before the doppelganger. There's several major problems, though. The doppelganger is fast. Better-than-A-grade fast. And you can't slow him down in any way, because he's intangible (a physical representation of an imposed time limit; a "time ghost", if you will).
To add insult to injury, even if you do manage to win, you are almost guaranteed to be awarded a D-grade, because once you go over S-grade time, every 5-15 seconds afterward will drop you one more full letter grade. By the way, since this is a challenge level, you can't equip any skills, and you can't boost your grade by collecting rings (AND unlike most challenge levels, there are no pick-ups to reduce your time). Even if you've managed to get an S-grade in the act proper, you will find yourself 10% more bald than when you first started playing the Doppelganger Race. Have fun. Oh and if the doppeleganger wins, you get to start the entire level over from the start.
Some of the "friend" challenges aren't a whole lot easier, especially Vector's two. In his Crisis City one, you end up fighting the wind as you try to guide him. In his Rooftop Run one, you have to chase notes and try to homing attack them back to Vector, but you end up having to basically memorize where the notes will go so you can get to them. The usual homing attack length seems shortened.
And introducing Charmy's friend challenge at Planet Wisp. My god...
Beating The Time Eater without getting hit gives you a trophy/achievement.
Shout Out: Several, which is only natural considering the nature of the game:
Shown Their Work: Classic Sonic looks exactly like the original Sonic design from the Genesis games, starting with the coloring details (black irises and flesh-colored eyelids), all the way to the animations and sound - even the Cheeky Mouth looks identical. Heís closer to his smaller and cuter Japanese design, as opposed to his attitude-infused Western design used on the box-art for the US versions of the original Sega Genesis trilogy (which Sonic Team admittedly hated).
All of the Classic Character designs featured in the game seem to be based off of these artworks specifically: , ◊, , , .
Orcas, likely as a reference to the one that chased Sonic in Emerald Coast in Sonic Adventure, help Sonic cross large bodies of water in Seaside Hill in the HD Sonic Generations. Emerald Coast does appear in the 3DS version, but not the HD one, and in the former, it chases both Sonics in their acts as it did in its debut.
The game lets you invoke this by allowing you to switch out the BGM of a stage or boss for any song you have unlocked in challenges. Yes, you are fully allowed to fight Perfect Chaos to the sound of Emerald Hill Zone if you really want to.
Sprint Meter: The Auto-Gauge skill turns the Boost Meter into this.
Stable Time Loop: The ending shows Classic Sonic attempting to perform the Air Boost, suggesting that he learned it by watching his future self do it in an earlier cutscene.
Stealth Pun: In the classic stage of Speed Highway there's a ring-related pun with a bell.
Tactical Suicide Boss: The Death Egg Robot is fought in an arena with mines classic Sonic can activate to stun the boss. No matter how many times he's damaged he will still do this. Though with the ending its obvious he was throwing the fight.
Took a Level in Badass: The Mad Convoy went from a nearly harmless sloth that could be defeated by a small arch that they could clearly see a mile away to a monstrosity in Generations! It is far larger than the Sonic Adventure 2 counterpart, it can destroy entire buildings without leaving a dent, and is able to contain gigantic saw blades and a rocket that gives it enough power to not only fly, but run up a wall. Not much better in the Classic version of City Escape where it is willing to tear down the city just to flatten a small blue mammal!
Modern Sonic, who can defeat Perfect Chaos without transforming into Super Sonic.
Also, the final hurdle of Rooftop Run for Classic Sonic is climbing a very tall clock tower fighting off lots of badnicks and performing tricky jumps along the way. Modern Sonic just runs straight up it in a matter of seconds.
In Sonic 3 the fire shield's dash was a basic mid-air dash that helped get to top speed or maneuver from a stop. Here it can effectively be a mid-air boost for the otherwise lacking classic Sonic.
Silver's psychic powers are shown to be considerably more powerful in this game than they've ever been shown to be before. He's also much faster, easily able to keep up with a boosting Sonic.
Five older characters* Bark the Polar Bear, Bean the Dynamite, and Fang the Sniper from Sonic the Fighters and Sonic Triple Trouble along with Ray the Flying Squirrel and Mighty the Armadillo from SEGASONIC Arcade and Knuckles Chaotix. appear on posters in City Escape - Three are wanted, two are missing.
Sonic Boom and the US Stardust Speedway theme, especially since the game use the JP/EU version by default and the 2011 port of Sonic CD was thought that it only had the JP/EU soundtrack at the time.
Unflinching Walk: After Classic Sonic defeats the Death Egg Robot and it falls over, he lands on his feet in a badass pose.
And then not one second later, he flinches as the robot explodes behind him.
Variable Mix: The BGM in Modern Sonic's Green Hill and Sky Sanctuary stages have a percussion track that changes tempo depending on how fast Sonic is moving. This is also used in Sonic Colors, in which the bass line in that game would vanish while boosting.
The speed shoes return in Classic Sonic's stages, so naturally the tempo picks up while using them.
The Death Egg Robot has two additional drum tracks as the fight progresses.
The Time Eater's theme seamlessly changes styles according to which Super Sonic is in control; from an orchestral style for Modern Super Sonic to an electronic style for Classic Super Sonic.