[[quoteright:256:http://static.tvtropes.org/pmwiki/pub/images/Sonic_Adventure_2_cover_4846.png]]

A sequel to the hit ''VideoGame/SonicAdventure'' and one of the SegaDreamcast's final releases, and a title to mark the [[MilestoneCelebration 10th anniversary]] of the series. It was also the last original ''Franchise/{{Sonic|TheHedgehog}}'' game to be made before Creator/{{Sega}} quit making consoles.

Mad scientist [[BigBad Dr. Eggman]] has a new plan to TakeOverTheWorld: reviving his grandfather's legacy, the abandoned space station "ARK". By using the Chaos Emeralds to power the ARK's most dangerous weapon, [[WaveMotionGun The Eclipse Cannon]], Eggman plans to strongarm the world into accepting his new world order. Helping him in this new scheme are two accomplices: Rouge the Bat, a FemmeFatale jewel thief with [[EnigmaticMinion shady motives]]; and Shadow the Hedgehog, a super-powered black hedgehog touted as "The Ultimate Lifeform".

Enter {{Chronic Hero|Syndrome}} Sonic the Hedgehog, who is mistaken for Shadow and falsely arrested by the law enforcement agency "G.U.N.". After breaking out of custody, Sonic is on a mission to clear his name, beat his new-found ebony rival and stop Dr. Eggman. Joining him are Miles "Tails" Prower, a kid genius and Sonic's best friend; and Knuckles the Echidna, who is searching for the scattered pieces of the Master Emerald after it gets shattered... [[HereWeGoAgain again]].

Got that? The plot is much {{darker|AndEdgier}} than the already-pretty dark ''Sonic Adventure'', as it contains vague allusions to [[ArmiesAreEvil a corrupt military]] and [[VileVillainSaccharineShow genocidal insanity]], while still retaining the cheese the series is known for. For example, Sonic being mistaken for a black hedgehog with red stripes despite having [[DudeWheresMyRespect saved the world repeatedly]].

This is the first game in the series -- bar racing and party games -- where you get to play as the villains, and by extension, the first where you get to play as Dr. Eggman. This game also introduced Shadow the Hedgehog and Rouge the Bat, both of whom would become series mainstays.

Like its predecessor, this game was also a big-hit critically and commercially, being hailed as a true swan song for the dying {{Dreamcast}}. It also, however, suffered some of the same PolygonCeiling-related criticism of CameraScrew and controls that its predecessor had. It also ditched the hubworlds in favor of a traditional level-by-level form of progression.

The game was re-released for the GameCube several months after the Dreamcast version as ''Sonic Adventure 2: Battle'' ([[SequelFirst before its predecessor's]] remake), which added more Chao stuff and gave 2-Player Mode a '''complete''' overhaul (which is probably where the "Battle" subtitle comes in).

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[[folder: Gameplay Types / Playable Characters: ]]

* '''Action Stage''' (classic Sonic style) -- Sonic / Shadow
* '''Shooting Stage''' (Gamma from ''VideoGame/SonicAdventure'') -- Tails / Dr. Eggman
* '''Hunting Stage''' (same as Knuckles from the previous game) - Knuckles / Rouge

There is also one driving stage each for Tails and Rouge. Beating one of them unlocks the single-player kart racing MiniGame, while beating the other unlocks the two-player option.

Following the success of its prequel, an [[UpdatedRerelease HD re-release]] of the game was released for {{Xbox 360}} and PlayStation3 respectively through XboxLiveArcade and [[PlayStationNetwork PlayStation Network]] on October 2nd, 2012 for $10; The additional two-player modes of ''Sonic Adventure 2: Battle'' are DownloadableContent for $3. The game has also been released on PC via {{Steam}} on November 19th, 2012, marking its official PC debut.

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!!This video game provides examples of the following tropes:

* AbandonedMine: Knuckles' search for shards of the previously shattered Master Emerald brings him to Aquatic Mine, an abandoned coal mine located within the vicinity of Pumpkin Hill that can be accessed via the sewers of Central City. This is aptly summed up by the opening lyrics of the stage's theme, "Dive into the Mellow": "Let's take a dive, in Aquatic Mine. Once was a coal pit, but now it's a water ride."
* AllegedLookalikes: Sonic is constantly being mistaken for Shadow, another hedgehog. Shadow has upturned spikes, is black and red (rather than blue), and uses hoverskates. Their only similarity is that they're both fast hedgehogs. This is especially bad since, at the speeds they normally move, their superficial similarities would result in being seen as "A blueish blur" and "a red blur." Additionally, Sonic's self-proclaimed girlfriend got them mixed up, not even when they were moving fast.
* AlmostKiss: [[spoiler:Knuckles and Rouge]] share one later on.
* AndNowForSomeoneCompletelyDifferent: Unlike its predecessor, each story cycles between the Action, Shooting, and Hunting playstyles instead of selecting a character and playing through his/her stages with that character.
** The Last Story consists entirely of this. In order, you play as Tails, Eggman, Rouge, Knuckles, then Sonic; Shadow takes on the stage's boss, and the FinalBoss uses Sonic and Shadow at the same time.
* AndYourRewardIsClothes: The rewards for getting all the emblems/A-Ranks for a character are an alternate outfit in 2P-Mode and an alternate kart in the kart racing minigame, although they ''do'' have some different attributes (Tails's alternate mech, for example, makes him a ''lot'' faster, but robs him of the ability to use special attacks).
* AnimatedAdaptation: Like ''Sonic Adventure'', adapted into the AnimeOfTheGame ''Anime/SonicX''.
* AnotherSideAnotherStory: The two sides - Hero and Dark.
* AntiFrustrationFeatures: If you lose a life fighting a boss, Omochao will usually spawn during your next attempt and give you a hint against defeating it. Whether or not the hint is helpful or [[CaptainObvious something you already figured out on your own]] varies.
* ArtificialStupidity: Chao have an odd habit of repeated jumping into the water feature of each garden, even when they can't swim. You'll sometimes get Chao that will immediately head straight back to the water right after being pulled out, and will repeat this several times. Thankfully, they can't drown.
* ArtisticLicensePhysics: After Eggman uses the Eclipse Cannon aboard the ARK to blow a chunk out of the moon ''as a warning shot'', everyone becomes concerned about the seriousness of Eggman's threats and possible responses -- never mind the fact that the effect on the tides alone would cause incalculable casualties in RealLife.
* ArmorPiercingQuestion: Rouge to Shadow, near the end of the Dark storyline.
* AutobotsRockOut: The final battle with [[spoiler:the Biolizard]] is accompanied by hard rock provided by {{Crush 40}}.
* {{Badass}}: Pretty much every character, but moreso Sonic, Knuckles and Shadow.
** BadassAdorable: Tails
** BadAssBookworm: Gerald Robotnik.
*** BadassGrandpa
*** BadassLabcoat
*** BadassMustache: see ItRunsInTheFamily
*** [[spoiler:HeartBrokenBadAss: After his granddaughter Maria's death.]]
** BadassInDistress: Both Sonic and Rouge end up in such spots.
** TookALevelInBadass: Even Sonic admits Eggman has stepped up his game this time.
* BelligerentSexualTension: Knuckles and Rouge show signs of this throughout most of the game.
* [[BigDamnHeroes Big Damn Antihero]]: Shadow manages to teleport [[BadassInDistress Rouge]] (and three of the Chaos emeralds, of course) off of Prison Island mere seconds before the whole island explodes. Note that he wanted to leave her to die, but the good that was still in him (represented by Maria) wouldn't allow it.
* BiggerBad: [[spoiler:The plot of the game is ultimately due to the actions of the late Gerald Robotnik, who orchestrated a plan to destroy the earth after what G.U.N. did to him. Of course, Shadow was the only one in on it, taking advantage of Ivo's megalomaniacal ways to get it done.]]
* BilingualBonus: An army called G.U.N. is not just a [[IncrediblyLamePun horrible pun in English]]; "gun" is also the Japanese word for "army".
** It also counts as a ShoutOut to [[MarvelUniverse a weapon used as an acronym for an organization.]]
* BittersweetEnding: The final story ends with [[spoiler:Shadow preventing the ColonyDrop by [[HeroicSacrifice sacrificing himself]]]].
* BlackEyesOfEvil: The Boom Boos in the haunted stages have black eyes blinking every few seconds. They will turn into the yellow-eyed, fanged-grinning boos once you hit them once.
* BlobMonster: Artifical Chaos on the ARK created by Gerald Robotnik.
* BossArenaIdiocy: King Boom Boo, like most other evil ghosts, gets weakened when he is exposed light, so why did he summon a small ghost to hold an hourglass that lets light into the arena?
* BossRush: Beating a story unlocks a minigame where you fight each of the bosses faced in that story one after the other.
* BossWarningSiren: {{Justified|Trope}} the boss fight against the Flying Dog. In the cutscene preceding the battle, Rouge is caught sneaking into a maximum-security vault and triggers an [[RedAlert alarm]] that alerts the boss to her presence.
* BreakoutCharacter: Shadow was originally meant to be a one-shot character for this game, but, not only did he become a series mainstay, he arguably got most of the development and plot focus in ''[[VideoGame/SonicHeroes Heroes]]'' and even starred in [[ShadowTheHedgehog his own game]].
* BreakTheCutie: Eggman does this to Tails and Amy by [[spoiler:shooting Sonic out of an explosive rocket]] before their very eyes, leaving them to think that [[spoiler:Eggman finally killed their best friend (don't worry, he used Chaos Control)]].
* BrokenPedestal: Even Eggman is surprised when [[spoiler:Gerald]] turns out to be a nutbar.
* TheCameo: Big the Cat can be seen during some cutscenes and even in the middle of some levels, as well as used in multiplayer... in the Dreamcast version. The GameCube version erased Big (sometimes with a Ring) in levels and replaced him with Dark Chao Walker in multiplayer, but he can still be found in Dark and Final cutscenes. The latest HD release does not return his multiplayer and Hero mode appearances, but reinserts him in most (but not all) levels.
* CameraScrew
* CardboardPrison: Prison Island, a prison and military base which, despite its name, is not TheAlcatraz. Eggman is able to break in all by himself with his Egg Walker, then gets out with Shadow. Later on Tails and Amy break in and get Sonic out.
* CerebusSyndrome: This game introduced Shadow the Hedgehog, which essentially started an arc spanned between this game (Barring a brief break from it in tone with ''VideoGame/SonicHeroes'') and ''VideoGame/SonicUnleashed'', which [[ReverseCerebusSyndrome ended it]].
* CharacterizationMarchesOn: At times, Shadow's behavior isn't too different from Sonic's. During [[DuelBoss the first battle]] against him, he even says "I'm the coolest!".
* ChasingYourTail: King Boom Boo and [[spoiler:the Biolizard]]
* ChekhovsGun: After seeing Shadow disappear in a flash of light as he used Chaos Control as many times as he did -- and for that matter, seeing [[spoiler:Sonic escape certain death via Chaos Control once before]] -- was it really such a stretch to believe that Shadow [[spoiler:[[NeverFoundTheBody had survived his plummet to Earth]]?]] On the same note, Tails mentioning that the fake Emerald had the exact same wavelength as a real Chaos Emerald came in handy later when [[spoiler:Sonic used Chaos Control to escape Eggman's trap]].
** Those mathematical symbols on Sonic's jail cell in Prison Island? [[LampshadeHanging The ones that Amy comments on?]] Why yes, those were the calculation performed by [[spoiler:Professor Gerald Robotnik to calculate how long it would take for the ARK to impact the Earth. You see the cell in all of Gerald's diary entries.]]
** Also, at the beginning Knuckles tells Rouge that the Master Emerald [[spoiler:is capable of nullifying the power of the Chaos Emeralds]]. At the end of the game, Knuckles needs to use the Master Emerald for that exact purpose.
* TheChessmaster: Shadow the Hedgehog, [[spoiler:who manages to take advantage of Eggman's ambitions in order to further his own hidden plan to get revenge on humanity for the G.U.N. massacre on the ARK 50 years ago.]]
** And Shadow's actions, in turn, were the result of [[spoiler:Gerald Robotnik placing subliminal messages and tampering with memories during Shadow's 50 year hibernation when he went mad.]]
** Rouge also counts for this [[spoiler:until her plan to obtain all of the Chaos Emeralds was stopped by Shadow at the end of the dark side story.]]
* ClassyCatBurglar: Rouge the Bat.
* ClearMyName: Sonic gets mistaken for the recently-freed UltimateLifeform and gets captured by G.U.N. (twice) early in the Hero story. Shortly before Sonic is captured a second time, Shadow steals a Chaos Emerald from a bank. Naturally, everyone assumes that this hedgehog is Sonic. One must wonder how color-blind the people of Sonic's world are. Possibly [[JustifiedTrope justified]] with the bank robbery, since it was night when it took place. G.U.N. has no excuse though.
* ColonyDrop: [[spoiler:The Last Story.]]
* CombatStilettos: Rouge wears these.
* ComicBookAdaptation: [[ArchieComics Archie]]'s ''ComicBook/SonicTheHedgehog'' comic book did not adapt ''Sonic Adventure 2'' originally. Instead they interrupted their own StoryArc for one issue, and used that issue to line up their own canon with that of the game, ending the issue where ''Sonic Adventure 2'' starts. The next issue began some time after the game ends, implying that everything in ''Sonic Adventure 2'' happened. Eventually Sonic Universe #2 showed what happened, with the story largely unchanged.
* TheComputerIsACheatingBastard: In the racing minigame, computer opponents can make 90 degree turns ''instantly'' without losing ''any'' momentum.
** In the levels near the end of each campaign where you face off against your same-mission-type Rival once again, they can use and abuse the usually 2-player-mode-only special attacks, but you cannot.
* TheComputerIsALyingBastard: In Mad Space, the hint computers are very uncooperative. The first hint for every emerald is written backwards[[note]]For example, Namgge Rotcod is really Doctor Eggman[[/note]]. The second and third hints aren't written backwards, but they ''tell you the reverse of what you need to know''. These computers are one of the reasons behind Mad Space's ThatOneLevel status.
* ContinuityNod: Tails is said to have got a Chaos Emerald for beating Eggman in Station Square, which happened back in [=SA1=].
** Also during the last story, Knuckles and Sonic stumble upon a temple-like structure that looks oddly familiar.
--->'''"Knuckles:''' "What is this place? [[VideoGame/SonicAdventure It looks just like the shrine of the Master Emerald.]]"
** And at that shrine [[spoiler:he says the same prayer of Chaos as Tikal in the previous game.]]
* CriminalDoppelganger: Pretty much the reason why Sonic is captured by G.U.N. twice and why him and his friends are constantly chased throughout this game. Justified in that the only times that Shadow is seen by the police is during the night and that there only happened to be one well-known anthropomorphic male hedgehog in the world up until that point. That justification does not apply to G.U.N. though, as they were aware of who Shadow was and should have been able to tell that Sonic was not the escaped UltimateLifeform once they got their hands on him (twice). To be fair, it is implied that Shadow was completely unaware of Sonic's existence up until Sonic defeated the Big Foot.
** Shadow might have known about Sonic's existence: when Eggman opened Shadow's pod, he verbally mentioned that Shadow was "not Sonic", and even thought that Shadow was Sonic, there to foil his plans already. However, Shadow had just woken up, so he might not have consciously understood what Eggman was saying.
* CutsceneIncompetence: Sonic's capture by G.U.N. at the end of City Escape.
* CuteLittleFangs: Rouge the Bat has them.
* CutscenePowerToTheMax: In the Hero Story, Sonic engages in a boss battle against the Egg Golem. In the same sequence in the Dark Story, the fight is condensed into one flying kick, complete with a ThemeMusicPowerUp.
* DamnYouMuscleMemory: Thanks to different controller design, the port for XBLA and PSN changes the action button to the B and circle buttons respectively, screwing with whoever is used to a Gamecube controller layout... until you realize that X or square have the same exact function yet aren't showcased as THE button.
* DarkerAndEdgier: ''[=SA1=]'' was darker than the game series up to that point, and ''[=SA2=]'' managed to be even darker. There's more than one character in the game who swears revenge on all humanity, and their motives are revealed in some cutscenes. Furthermore, Dr. Eggman, [[VillainProtagonist who you can play as in this game]], is willing to use a "weapon of mass destruction" (yes, it is actually described as that in the game) as a means of trying to intimidate people into surrendering to his empire, by threatening to fire it at inhabited parts of Earth, and unlike the rest of the franchise he's played mostly a serious character with very few humorous moments1. He demonstrates its power by firing it at the moon, and it happens to take quite a chunk out of the moon for that matter... add to that, of course, the government conspiracy sideplot, that involves them assassinating numerous innocent people on-board the ARK (with Maria even dying onscreen). Outside maybe the Archie comics, this was perhaps the grimmest depiction of Sonic yet at this point in time.
** Though the overall tone of some [[ShadowTheHedgehog future]] [[VideoGame/SonicTheHedgehog2006 titles]] was a bit darker, NOTHING in the rest of the series comes close to the last act of this game. [[spoiler:Gerald's diary/execution speech rivals the most depressing and terrifying messages left behind in any [[SurvivalHorror Survival Horror]]]]. It helps that both voice actors for Gerald were incredibly good at getting his gut-wrenching despair and hatred for humanity across.
** [[spoiler:Sonic's DisneyDeath at the near-end of both the Hero and Dark stories]] are notable in that, while filled with [[LikeYouWouldReallyDoIt like-you-would-really-do-it]], the game seems to be pretty [[IncrediblyLamePun dead]] serious about it, despite the one involved being [[spoiler:the series' namesake]]. [[UpToEleven Even more so]] with the [[RashomonStyle version of the same scene]] seen in the Dark story, as there's literally ''no'' clue that [[spoiler:Sonic would survive]] ''despite'' NoOneCouldSurviveThat. (That is, until [[spoiler:he]] showed up as the FinalBoss.)
** The game also appears to kill off one of its main characters at the end. Future titles would retcon this, as said character turned out to be too popular to die.
** It should also be noted that Maria was an innocent twelve year old. Yes, an innocent twelve year old is shot dead in a Sonic game.
* DecoyProtagonist: Eggman for the Dark side is this gameplay-wise. Four of his levels are in the first half of the game, but aside from boss fights he only gets one level in the second half.
* DefaceOfTheMoon[=/=]DetonationMoon: Eggman blows up half of the moon with just six of the seven Chaos Emeralds, threatening to do the same to any country that doesn't submit to him. (Oddly, it's perfectly fine in some later entries, and still half-blown-up in others.)
* DefeatMeansRespect: Knuckles and Rouge after the whole Meteor Herd incident.
* DiesWideOpen: Maria, in a very creepy subversion - she slumps against a control panel with her eyes closing, but they slowly open again ''after'' she's died.
* DifficultySpike: The Hero story has a huge one that begins at Death Chamber.
* DisproportionateRetribution: [[spoiler:Gerald held all of humanity responsible for Maria's death, when it was really just G.U.N..]] Justified as he is completely insane and not inclined to be reasonable.
* DoNotAdjustYourSet: In the second variation Eggman hijacks the airwaves to announce his ultimatum: [[YouHave48Hours twenty-four hours]] until he destroys the earth unless the world leaders agree to surrender it to him. And in the third variation however, in the last story after all of the Chaos emeralds have been gathered the airwaves are hijacked once again [[spoiler:only this time it's showing a tape of the late Gerald Robotnik giving his FinalSpeech which outlines his ColonyDrop aimed at earth]].
* DontTouchItYouIdiot: Inside the space shuttle, Sonic tells Knuckles not to touch the lever to get the remaining pieces of the Master Emerald after the shuttle hits a meteor. Knuckles does it anyways.
-->'''Sonic''': OH NO! DON'T TOUCH THAT LEVER!!
* DragonWithAnAgenda: Shadow only helps Eggman [[spoiler:in order to trigger Gerald's ColonyDrop plan to avenge Maria's death]].
* DuelingPlayerCharacters: The game has the story split into two sides the 'Hero' side with Sonic, Tails & Knuckles, and the 'Dark' side with Shadow, Eggman & Rouge. Each character is matched to another, and fights their counterpart several times through the course of the game. Again, the fights are played from both perspectives.
* DummiedOut: The game contains a hidden level used by the developers for testing the game engine. It is only accessible by hacking or, in the case of the Xbox 360 and PS3 versions, [[http://www.youtube.com/watch?v=IR01VNdsMXs a glitch.]]
** [[http://www.youtube.com/watch?v=q8Im0r86dKE Here]] are some unused sound clips from the game. There is also some unused [[http://www.sonic-cult.org/dispart.php?catid=3&gameid=5&subid=1&artid=16 sound clips from Omachao]].
** There is also unused dialogue for Shadow for multiple things, such as being grabbed by a ghost, which is impossible due to not having ghosts in his levels.
* DyingDeclarationOfHate: [[spoiler:Prof. Gerald gives one to all of humanity before GUN executed him, blaming them for the death of Maria and that he has planned their future demise by programming the ARK to crash towards earth.]]
* {{Eagleland}}: The United Federation is ''heavily'' Type 2.
* EarthShatteringKaboom: The Eclipse Cannon can produce one of these if all seven emeralds are gathered together, and Eggman demonstrates this on the moon. [[spoiler:Gerald Robotnik instead has a ColonyDrop program for the ARK kick in when all seven emeralds are collected, so as to make ''absolutely sure'' this occurs, compared to Eggman, who just intends to raze countries that don't submit to him.]]
* EasilyCondemned: Sonic falls into this when he was on the run from GUN after he was framed for stealing a Chaos Emerald.
* EasterEgg: [[http://www.youtube.com/watch?v=Ig1CkB-YetE Big The Cat IS...EVERYWHERE! (except in the Gamecube version)]]
* EleventhHourSuperpower: For the TrueFinalBoss, Sonic and Shadow both go Super to defeat it.
* EnemyMine: The hero and dark teams both team up in the final story [[spoiler:to prevent the ColonyDrop.]]
* EternalEngine: Trope Namer and an action stage in the Hero Story.
* EvenEvilHasStandards: Eggman may want to use the Space Colony ARK to take over the Earth, but he balks at the idea of using its power to kill all humanity.
* EvilCounterpart: Shadow to Sonic.
** Eggman to Tails, and Rouge to Knuckles as well.
* EvilVirtues: For Eggman, it's hard work. In the ending, Eggman reveals that he aspired to Gerald's great accomplishments from the time he was little.
* {{Expy}}: [[GiantSpaceFleaFromNowhere King Boom Boo]] and his minions are strikingly similar to [[VideoGame/SuperMarioBros King Boo and his ghosts]].
* ExtremityExtremist: Knuckles and Rouge use only punches and kicks, respectively.
* [[EvilTwin "Fake" Twin]]: Sonic considers Shadow this due to the latter framing him for stealing a Chaos Emerald. It's also hinted that Shadow himself thinks Sonic is this to him, thinking Sonic was trying to copy him.
** "Implied"?
---> '''Shadow:''' "[[HannibalLecture You, comparing yourself to me? Ha! You're not even good enough to be my fake!]]"
* {{Faceship}}: Eggman may have gotten his love for this from Gerald, as the Space Colony ARK was apparently made in Gerald's likeness.
* FailedASpotCheck: Maybe one of the most egregious examples ever. The fact that EVERYONE seems to mistake Shadow for Sonic is pretty bad, but the fact that Amy Rose - who fawns over Sonic nonstop - somehow fails to notice that this particular Hedgehog has the wrong hair, shoes, and ''colour'' to be Sonic until she's grabbing onto him is pretty bad. Oh, and she also fails to notice the series BigBad standing right next to him.
* FatBastard: Dr. Eggman.
* FinalSpeech: [[spoiler:Gerald gives one before being executed by G.U.N.. It basically outlined his ColonyDrop plans and pointed out his DisproportionateRetribution to all of humanity.]]
** [[spoiler:Shadow gives one believing that he has finally fulfilled Maria's final wish as he plummets to the Earth. Keep in mind that Sega originally planned to keep him KilledOffForReal when the game was released.]]
* FoeRomanceSubtext : Knuckles and Rouge, sort of.
* FogFeet: A Chao that plays with bats will eventually have its legs disappear; it'll hover above the ground instead.
* {{Foreshadowing}}: There's a bit during the cutscene right before Final Chase, where Rouge reads about "Project Shadow" which [[spoiler: not only implies there is more to Shadow's origins than originally shown, but also features a split second shot of a picture of the Biolizard (albeit at a low resolution because of the Dreamcast's limitations)]].
* FrameUp: Shadow framed Sonic with the theft of the green Chaos Emerald. Somewhat deconstructed, as its implied that Shadow did not intend to frame Sonic for the deed, and in fact, had never even ''heard'' of Sonic up until after he stole the emerald, specifically shortly after Sonic defeated Big Foot. In fact, through most of the game, Shadow believed that Sonic was copying ''him.''
* FunWithAcronyms / SpellingSong: Averted and played straight respectively with Eggman's theme, "E.G.G.M.A.N." -- it's spelled out a few times at the beginning by a modulated voice in the background, but it doesn't seem to stand for anything. (Amusingly, it's also one of exactly two songs ever to use the exact phrase "[[Music/TheBeatles I am the Eggman]]".)
* FurryConfusion: Rouge the Bat is a playable character, but regular Bats can be found and rescued from the stages. Most confusing is the fact that the Bat is only in this game.
** The level ''Death Chamber'' takes it even further: It has actual, real-life bats. That's three different kinds of bats in one game!
* GameMod: [[http://info.sonicretro.org/Super_Sonic_Adventure_2 With the PC release of this game on Steam, the mod floodgates have opened starting with this mod that allows the use of Super Sonic in all levels.]]
* GameplayAndStorySegregation:
** All three of the good vs. evil battles are ultimately seen to end in draws, even though you have to win the actual fight for whichever side you're playing.
** When facing Egg Golem in Hero Story, you have to (as Sonic) get behind it and jump up platforms on its back in order to homing attack its head's weak point to damage it; you need to do this several times. In the Dark Story, it's defeated by Sonic in a cutscene where he takes a giant leap at its weak point (a leap which, incidentally, is not possible when ''playing'' as Sonic) and [[OneHitKO defeats it in one kick.]]
** Knuckles and Rouge actually run faster than Sonic and Shadow in gameplay.
** Averted in the final boss battle. Shadow's in-story failing super form is represented by his ring count starting lower and lower each time you switch to him after a certain point into the battle.
* GameplayGrading: You are ranked at the end of a stage based on your score (although you can automatically earn a perfect A if you collect ''every single ring'' in the stage). All 3D Sonics following this game would use a similar ranking system.
* GameplayRoulette: Not as pronounced as in ''[=SA1=]'', but still present.
* GetBackHereBoss: The second Sonic vs. Shadow battle
* GettingCrapPastTheRadar: Various BGM tracks have suggestive lyrics, but Wild Canyon takes the cake. One of the radars caught this one; the ESRB rating has "Mild Lyrics" as a descriptor. But apparently, SEGA's translators didn't.
-->''"They wanna [[DoubleEntendre play with my Emeralds]]? They're playing with the wrong guy!"''
-->''"Yeah, Rouge, she's sexy and smooth! A double cross spot-thief, that's [[DoubleEntendre out for my jewels]]."''
** That may not be intentional though, as the song does mean it literally.[[note]]The lyrics were in reference to the fact that Rouge the Bat and Dr. Eggman attempted to steal the Master Emerald, and in the case of the former, its pieces.[[/note]]. However, they do use "damn" in at least 2 different songs, and the "Mild Lyrics" did not appear on the back of the box until Sonic Adventure 2: Battle, as the original did not have that.
** Shoot, [[MsFanservice Rouge's]] [[{{stripperiffic}} design]] by itself does this.
* GiantSpaceFleaFromNowhere:
** King Boom Boo.
** Also [[spoiler:the Biolizard when it fuses with the space colony and becomes the true final boss, Finalhazard. The Biolizard itself doesn't count, since, technically, it's featured in the Project Shadow report Rouge downloads from the main computer, though the resolution makes it hard to discern its image]].
* GotVolunteered: As Sonic and his friends approach to the center of Eggman's pyramid base, they needed a key to get inside. Sonic suggests that Knuckles should find it since he's "the world's greatest treasure hunter", much to his chagrin.
* [[PapaWolf Grandpa Wolf]]: Gerald loved his granddaughter Maria, [[spoiler:[[KnightTemplar and once she was killed, he almost destroyed the world.]]]]
* GRatedSex:
** Chao mating, combined with a HappyDance.
** Not to mention some of the lyrics in Knuckles' level's songs, especially Wild Canyon.
* GratuitousEnglish: Sonic in the Japanese dub, as usual for him. Notably, his rank comments are mostly in English (with the exception of B rank, where he literally says "Too easy! Rakushou da ze!" in Japanese and "Too easy! Piece of cake!" in English), plus his comment of "Hey guy, take care!" after beating Big Foot, as well as a few other examples.
* GratuitousJapanese: "Sayonara, Shadow the Hedgehog." Only in the English dub, since...
** In the English version, Dr. Eggman still says "Yoshi!" when he completes a level ("Yoshi!" being Japanese for "Yes!/Alright!").
** A strange case of this comes in "Kick the Rock!", as it's more or less Gratuitous English-Pronounced-in-a-Japanese-Way. The lyrics go "Ekidona, that's what I'm representin'" - "Ekidona" is "echidna" spelled phonetically in Japanese (the singer then adds AccentUponTheWrongSyllable by pronouncing it "Eki-DOH-na").
* GratuitousSpanish: In the Japanese dub, the line "Sayonara, Shadow the Hedgehog" was "Adios, Shadow the Hedgehog".
* GravityScrew:
** Crazy Gadget and its switches that make Sonic walk on the ceiling and walls. A memorable part at the end of the level involves navigating a series of these in space, and [[ThatOneLevel it's pretty tough]]. There are other examples in the part of EternalEngine where Tails floats inexplicably, and Cosmic Wall, where Eggman's mech can jump incredible heights due to lowered gravity.
** Rouge's final level, [[NintendoHard Mad Space]], uses the 'planetoid' subtype very excessively, though not nearly as well as the [[OlderThanTheyThink later]] ''VideoGame/SuperMarioGalaxy''.
* {{Greed}}: Rouge the Bat, [[spoiler:who only works with Eggman so she could have a chance to steal the Chaos Emeralds, the Master Emerald, and in addition finish the job for the government where she will get paid with even MORE jewels. [[WordOfGod Oh yes, and she also wants to add her crush and rival Knuckles' heart to that list.]]]]
* GreenHillZone: Rouge's first level, Dry Lagoon, is a textbook example despite being set in a desert. [[spoiler:The TropeNamer [[NostalgiaLevel makes a return appearance]] if you [[OneHundredPercentCompletion collect all 180 emblems.]]]]
* GrindBoots: Sonic's shoes were redesigned into this. Shadow's are also able to grind.
* GuideDangIt:
** The hidden [[http://www.youtube.com/watch?v=G5lYzoBsaTo Secretary]] and [[http://www.youtube.com/watch?v=ZCL3Zm278_g Maria]] menu themes.
** Some of the "Find the Lost Chao!" Missions are near impossible to complete without looking in a guide. In particular, all the steps that you need to do in [[VeryDefinitelyFinalDungeon Cannon's Core]] to find that Chao is pretty daunting.
*** While not as hard as Cannon's Core, the lost chao in Radical Highway is particularly easy to miss.
** Cannon's Core: [[BlatantLies Knuckles' mission is not that hard]]... If you found the really well hidden Air Necklace in a previous level.
** Most of the different chao can be made by experimenting around. The chaos chao however have requirements that are so specific you'd probably never know they even exist unless you look up a guide. One of the requirements is giving exactly one of each of the TWENTY-ONE different animals to the chao. And once you do that it doesn't even let you know anything changed until a couple hours later when the chao finally evolves into a chaos chao.
** In some of the [[NintendoHard Hard Mode]] missions for Knuckles/Rouge levels, some of the emerald pieces are hidden very obscure areas that they won't show up on the radar no matter where you look, and the hint computers don't help much either. Special mention goes to the second emeralds of Wild Canyon and Aquatic Mine.
** In most levels, there is a golden beetle enemy that appears, then disappears after a few seconds. Destroying one of these beetle enemies really helps your rank in score-based missions (the first mission, the timed mission, and hard mode) as doing so gives you 1000 points. However, some of them are very easy to miss, particularly those in Pumpkin Hill, Cosmic Wall, Final Rush, and Final Chase.
* {{Hammerspace}}: How Knuckles carts around his emerald pieces. (At least Rouge can claim to have a [[VictoriasSecretCompartment compartment]]).
* HannibalLecture: In their first battle, Shadow gives one to Sonic, gloating that he isn't good enough to be his fake, but [[ShutUpHannibal Sonic responds with swearing to make him eat his own words]].
* HeroAntagonist: G.U.N..
* HeroicSacrifice: [[spoiler:Shadow]], after turning face in what is quite possibly the most famous example of this trope in a Sonic game. Overlaps with RedemptionEqualsDeath.
* HintsAreForLosers: In Knuckles and Rouge's levels, finding the Master Emerald Shard (or Door Key or Chaos Emerald) in a short amount of time without using any hint monitors would earn you a Perfect 2000 point bonus. In Rouge's Mad Space level, the hint monitors are reversed, as the hints either say the opposite of where the Emerald Shard really is, or are [[Main/SdrawkcabName literally written backwards]].
* HoistByHisOwnPetard: At one point, Eggman sics the Egg Golem onto Sonic. In Dark Story, Sonic destroyed the restraining bolt on the Egg Golem. [[AIIsACrapshoot Guess what it does with Eggman afterwards?]]
* HongKongDub: When the line takes longer to say in English than it did in Japanese, the next line will start while the previous one is still going... even when the next line is spoken by the same character. (It does lend a strange David Mamet flavor to the dub.)
* HotterAndSexier: The debut of [[MsFanservice Rouge the Bat]] is enough to make the game this in comparison to the other titles.
* HumansAreTheRealMonsters: Shadow's initial viewpoint. As well as Gerald's.
* HypocriticalHumor:
** In one scene where Eggman steals the Master Emerald from Knuckles:
---> '''Rouge:''' "Thief!"\\
'''Knuckles:''' [[LampshadeHanging "Look who's calling who a thief..."]]
** In the last story where Eggman learns about his grandfather had planned for the ARK to crash towards earth:
---> '''Eggman''': "That mad scientist!"\\
'''Amy''': "That should be you, right?"
* ImageSong: All six playable characters, as well as the NPC Amy have one.
** IAmSong: Sonic's, Knuckles', and Eggman's: '' It Doesn't Matter'', ''[[BoastfulRap Unknown from M.E.]]'', and ''[[VillainSong E.G.G.M.A.N]]'' respectively.
* InCaseOfBossFightBreakGlass: Every G.U.N. mech.
* InsultToRocks: Shadow finds it almost insulting that G.U.N. mistook Sonic for him.
-->'''Shadow:''' "[[HannibalLecture You're not even good enough to be my ''fake'']]!"
* InterruptingMeme: Some of the dialogue have characters interrupting each other's sentences right before they end it.
* IronicEcho: "Sayonara, Shadow the Hedgehog."
* ItRunsInTheFamily: The Robotnik family [[StrongFamilyResemblance mustache]]!
** InTheBlood: [[spoiler:Batshit insanity]], too.
* IWasJustPassingThrough: Two instances of this had happened.
** Shadow shrugs off of the fact he saved Rouge's life, and says that he was saving the Chaos Emeralds.
** Knuckles also does this to Rouge after saving her from falling into the lava, claiming that he was saving the pieces of the Master Emerald.
* JerkWithAHeartOfGold: Knuckles showcases this when he rescued Rouge from falling into the lava pit after their fight for the Master Emerald shards. He then apologized for hurting her in their previous battle.
* JustAKid: Eggman insults Tails for being a kid in the beginning of their first battle:
-->'''Eggman''': You're just a kid! You couldn't beat me in a hundred years, stupid little fox!
* JigglePhysics: Different parts of different characters have this, the most notable examples being Sonic & Shadow's quills, and Rouge's ears and [[GagBoobs breasts]] (yes, they really did animate a cartoon bat's breasts).
* JumpScare: The boos in the haunted stages will pop up at the character's face while growing large in form before disappearing. They pop up in miniature forms if the character gets close to it or just pop up from random places unseen.
* KarmaHoudini: G.U.N. Actually averted in that you can destroy their robots and the fact that you can even damage the pilots controlling Big Foot, Hot Shot, and Flying Dog.
* KeepItForeign: The iconic line, "Sayonara, Shadow the Hedgehog", is replaced with "Adios, Shadow the Hedgehog" in the Japanese version.
* KickChick: Rouge, to contrast Knuckles' punches only attack style.
* KillSat: Space Colony ARK.
* KnightTemplar: G.U.N. will do almost anything to preserve world order. They got better eventually. Also, Gerald believed his [[spoiler:ColonyDrop against humanity]] to be "justice" for the ARK Disaster.
** KnightTemplarBigBrother: Shadow was a surrogate one for Maria, [[spoiler:until Amy reminded him what Maria really wanted.]]
* KillTheCutie: [[spoiler:Poor Maria.]]
* LargeHam: Eggman, Eggman, [[RuleOfThree Eggman.]]
* LawyerFriendlyCameo: The President.
* LeeroyJenkins: Sonic, even moreso than usual. He's concerned only with stopping Eggman and pays little attention to Tails' strategy sessions.
* {{Leitmotif}}: Many songs throughout the game feature the same recurring guitar riffs, along with some shared lyrics (for instance, in City Escape and the chorus of Supporting Me). It's only at the end of the game that they come together into the game's signature theme, Live and Learn.
* LevelGrinding: Getting an A by getting the set amount of rings may require this. Completing all of the Chao Garden emblems will require quite a bit of this.
* LuckBasedMission: Treasure hunting levels have some of this by design--emeralds may randomly spawn in a location that cannot be reached without hitting a certain switch, for instance, making them harder to find by merely sweeping the stage. Chao karate, with its uncontrollable AIRoulette and CriticalHit mechanics, is an example that can be muted by sufficient LevelGrinding. Chao races feature an actual hidden luck stat in some races along with randomized tripping.
* MadScientist: [[spoiler: Dr. Gerald Robotnik was sane prior to GUN's assault on the ARK. After that his disillusionment with humanity drove him to strike back with his creation.]]
* MilestoneCelebration: Coincides with the 10th anniversary of the original game. As such, collecting 180 emblems will [[spoiler: unlock a 3D version of Green Hill Zone.]]
* MiniMecha: Tails and Eggman's stages consist of piloting small mechs through their stages, with Tails' Cyclone being his new Tornado airplane [[TransformingMecha that swaps its wings for a set of legs]] and Eggman's being his hoverpod with legs and guns attached.
* MisplacedRetribution: Gerald's plot to get revenge from beyond the grave was focused on bringing suffering and ruination to people (Pretty much the entirety of humanity) who were not responsible for the ARK Incident or the murder of Maria and his colleagues.
* MoreThanMindControl: It's subtly implied that Gerald "reprogrammed" Shadow to go along with his genocidal ColonyDrop plan.
** More than implied. He "designed its mind to be perfect. Pure..."
* MouthStitchedShut: The Boom Boos have these that conceal their {{Slasher Smile}}s.
* [[MrViceGuy Ms Vice Girl]] / {{Anti Hero}}ine: Rouge is secretly a government agent whose job is to protect the world from threats like Eggman and Shadow, and turns out to be GoodAllAlong. Also, her passion is jewels, and in her free time she goes around greedily stealing gems wherever she can find them, not caring whether they're, y'know, necessary to the balance of the planet or not. Somehow, these two things never seem to clash -- in fact, she's apparently only a good guy some of the time because the government pays her in jewelry.
* MsFanservice: This game introduced the world to Rouge the Bat. She has a big bust, [[{{Stripperific}} a revealing outfit]], combined with JigglePhysics, [[HartmanHips and wide hips]] that go hand in hand with a shapely rear.
* MusicalNod: [[EarWorm City Escape]] appears as an instrumental in [[http://www.youtube.com/watch?v=EUZBu0gELsw Mario & Sonic Olympic Winter Games]].
** The CallBack to [[VideoGame/SonicAdventure Lost World]] in Cannon's Core is also this. There is a water slide similar to the aforementioned level in Adventure, and the music changes to the drum beat of the music that was used in the water slide part of that level.
*** The music played during the cutscenes before and after the Biolizard reuses some parts of the music played during Lost World as well.
* MythologyGag: The Egg Golem first appeared as the boss of Sandopolis Zone in '''VideoGame/Sonic3AndKnuckles''.
* NeverSayDie: Averted '''big time!''' Dr Eggman comments in one of his story reminder monologues that killing Tails will be a pleasure, Sonic is told on a number of occasions that he is going to die. [[TheLoad Amy]] is threatened with death a couple of times. Though Eggman never actually uses it, carrying that big pistol about in a couple of the cutscenes certainly shows that he means SeriousBusiness.
* NoCommunitiesWereHarmed: The nation's capital is based on UsefulNotes/SanFrancisco, where SonicTeam was based at the time. Route 101, Route 280, and Mission Street all reference major roadways in the city. The SambaDeAmigo references in Mission Street may serve as a dual reference to the Mission District, which was (and is still somewhat) largely Hispanic. Shadow's Radical Highway level is also based on the Golden Gate Bridge.
* NoConservationOfEnergy: When Sonic and Shadow use Chaos Control to stop the falling ARK, the colony comes to a complete halt. The explosion of light was no where near big enough to be equal to its previous momentum. Of course, SEGA has never bothered to explain exactly ''how'' Chaos Control works, [[AWizardDidIt so... ]]
* NoSidepathsNoExplorationNoFreedom: ''Adventure 2'' does away with Adventure fields and the ability to select characters, instead having the player experience every gameplay style in the same story, with stages coming one after another in sequence. Upgrades are found within the stages as well.
* NostalgiaLevel: Collecting all 180 Emblems rewards you with a 3D version of [[spoiler: GreenHillZone from the original VideoGame/{{Sonic the Hedgehog}}.]]
* NotBad: In the Hero story in the first Sonic/Shadow boss battle, Shadow, who is defeated, says this to Sonic that he wasn't bad for an impostor.
* NotMeThisTime: At the start of the Last Story, Knuckles wrongly accuses Eggman of [[spoiler:sending the ARK on a crash course to Earth.]]
-->"I'd have done this a long time ago if I had the chance!"
* NotSoDifferent: Eggman and Tails share a moment on the ARK observation deck at the end.
* OhCrap: Sonic's reaction when Eggman traps him in the capsule pod rigged with explosives.
* OmnicidalManiac: [[spoiler:Gerald]] did ''not'' take Maria's death well.
* OneWingedAngel: The Biolizard becomes Finalhazard when he fuses himself with Space Colony ARK.
* OutGambitted: Sonic and Tails plot to give Eggman a fake Emerald that will explode when it's put into the Eclipse Cannon, thus making it unusable. Having a feeling that this would happen, Eggman seals Sonic inside a rocket, causes Tails to accidentally spill the beans, and shoots Sonic out of the Ark to a most certain death. Good thing Sonic still has that fake Emerald in his hands, and it is powerful enough for Sonic to use Chaos Control...
** See YouJustToldMe.
* PathOfGreatestResistance: Because Sonic and Shadow can use the Homing Attack, which was introduced in [[Videogame/SonicAdventure the previous game]], this game has paths identifiable (and accessible) only by finding a trail of stationary midair enemies. This is most commonly used to begin an expert path or for a shortcut; there are only two levels where this is actually required (excluding hard mode): Metal Harbor and Crazy Gadget.
** It's quite common in hard mode for there to be a trail of enemies that stops halfway across a bottomless pit and a trail of rings that begins where the trail of enemis stops. In these areas, you must cross the enemy trail, then light dash on the trail of rings to get across. [[note]] This is harder to do as Sonic because if you are too early on the light dash, you will do a bounce attack instead and fall to your death.[[/note]]
*** Crazy Gadget has an area like this in all missions with a grind rail and spring below the ring trail. [[note]] Because the grind rail acts as a safety net if your timing is off, this is a great area to practice this method of grossing gaps.[[/note]] Unfortunately, the rail is removed in hard mode.
* ThePasswordIsAlwaysSwordfish: The code to access Project: Shadow and to fire the [[KillSat Eclipse Cannon]] is "Maria".
* PatrickStewartSpeech: Delivered by Amy of all people to convince Shadow to turn face.
* PoliceAreUseless: Even ''Sonic'' lampshades this.
* PolygonCeiling: Bad controls and camera as its [[VideoGame/SonicAdventure predecessor]].
* PosthumousCharacter: Both Gerald and Maria Robotnik.
* PowerCopying: [[spoiler: Sonic survives Eggman's attempt to blow him up in space by using Tails' fake emerald and remembering how Shadow's Chaos Control worked.]]
* PowerStrainBlackout: [[spoiler: Sonic nearly suffers one as a result of the aforementioned PowerCopying.]]
* PreviouslyOn: Upon continuing a story segment, the character that you're about to play as will give a brief summary of what's happened up to that point and what they're about to do. For the Last Story, Amy narrates for the Cannon's Core stage.
* ProductPlacement: Due to Sonic now wearing Soap Shoes, ads for them are all over the game.
* PromotedToPlayable: Eggman.
* PsychoPrototype: [[spoiler:The Biolizard]] is this to Shadow the Hedgehog.
* PunctuatedForEmphasis: Eggman when you get an A-Rank.
--> "NOW YOU KNOW WHY I! AM! THE BEST!"
* ReactorBoss: EternalEngine, in which Tails fights ARK's power generator.
* RedemptionEqualsDeath: [[spoiler:Shadow]], originally. Later {{retcon}}ned.
* RemixedLevel: Many levels use the same geometry as other levels the character's counterpart goes through, just with different decorations and locations. The noticeable example are Knuckles and Rouge's respective levels Wild Canyon and Dry Lagoon.
* RidiculouslyCuteCritter: Improves on ''[=SA1=]'''s chao-raising system with the addition of Hero and Dark chao. The system would go through a complete overhaul for the [=GameCube=] versions.
* TheRival: Sonic/Shadow, Tails/Eggman, and Knuckles/Rouge.
** EvilCounterpart
** RivalsTeamUp: Cannon's Core
* SanitySlippage: Gerald Robotnik, as his diary indicates, definitely went through one after Maria died; ''I became scared as I could no longer control my thoughts... All I knew was that I wanted it to end...''
* SarcasticDevotee: Even if [[spoiler:she was a double agent]], Rouge plays one to Eggman, especially when she mocks him for throwing a tantrum when he realized Sonic interrupts his conversation with the President through the screen.
* SayMyName:
** Shadow yells out "MARIA" when an enemy kills him in levels. Also does this a lot of time during his flashbacks.
** Amy and Tails both do this seperately when Sonic exploded in the capsule [[spoiler:or so they thought.]] Tails does this whenever he dies in a level.
* SceneryPorn: Ten years later, it still holds up well.
* SchizophrenicDifficulty: Since you jump around from playing style to playing style, this can be in effect if you are much better at some characters than others.
** Also, each stage has the same five missions in the same order. Depending on which character you are using, some of the missions will be easier or harder than usual. Tails and Eggman's stages have very few rings and LOTS of enemies, so the second mission, 'Collect 100 Rings!', is harder for them than it would be for other characters. The timed missions for Knuckles and Rouge tend to be harder than their 'Complete Hard Mode' missions since for them, while the emeralds are in very annoying and hard to reach places in Hard Mode, they're in the same place each time.
* SealedEvilInACan: Shadow.
* [[NintendoHard Sega Hard]]:
** Every 5th mission for a level has a Hard mode challenge, where the level's difficulty borders on downright frustrating. Many consider Eternal Engine, Crazy Gadget, Mad Space, and Cannon's Core to be punishingly difficult already. [[OhCrap Then you find out that even]] ''[[ThatOneLevel they]]'' [[OhCrap have]] [[UpToEleven Hard Modes themselves...]]
** Getting A-Ranks on the early Action and Shooting stages aren't ''too'' obscenely hard, but roughly halfway through the game they become incredibly annoying without resorting to SequenceBreaking shortcuts to get massive time bonuses. And let's not even talk about the Hunting Stages, the system for which has been tweaked to be ''even more annoying''.
* SelfImposedChallenge: Try beating Knuckles' section in Cannon's Core WITHOUT the Air Necklace.
* SequelDifficultySpike: Minor, but the ''Battle'' port and the rerelease significantly raised (read: doubled) the requirements for an A-Rank in Eggman's final level, Cosmic Wall.
* ShiftingSandLand: All of the stages surrounding and inside Eggman's Pyramid Base.
* ShoutOut: To ''{{Nights}}'' and ''SambaDeAmigo''.
** There are also a couple references to ''PhantasyStarOnline''. Some unlockable alternate costumes on the Gamecube version are similar to what the characters in said game wear, and there are billboards advertising it scattered throughout the city levels.
** During the famous scene of Eggman's video-message to the world, the mixture of Japanese and English text behind him is awfully reminiscent of [[DigimonAdventure Digivolutions.]]
** The entire final sequence where Sonic and Shadow [[spoiler:use Chaos Control to push ARK back into orbit]] is a reference to the climax of MobileSuitGundamCharsCounterattack.
** Some of the Achievements/Trophies for the HD remake are this. [[GuiltyGear Heaven Or Hell]] & VideoGame/BeyondGoodAndEvil mainly.
** Every time you get a B-Rank in Knuckles' stages, Knuckles will say "Yeah, I feel good!", which sounds similar to one of Music/JamesBrown's hit songs "I Feel Good".
* SlasherSmile: The Attack Boos in the haunted stages have a scary, fanged-toothed smile.
* {{Slap Slap|Kiss}} AlmostKiss: Knuckles and Rouge literally have this going on when they meet up in Meteor Herd.
* SlidingScaleOfLinearityVsOpenness: The main game is level 3. There are multiple paths through each level, with more being unlocked as you gain more items, and you can replay levels with different goals for more emblems. The chao raising mini-game, though, is decidedly level 6, for the game gives you no overall goal to accomplish in raising your chao.
* SoundtrackDissonance: The themes for all of his stages seem to imply that [[ProudWarriorRaceGuy Knuckles]] is gangsta.
* StealthPun: The style of music played in Shadow's White Jungle stage, minus the {{Amen|Break}}.
* StepfordSmiler: [[spoiler:In the end of the last story, Sonic is noticeably grieved of Shadow's sacrifice, and when Amy goes to ask what's wrong with him, he assures that it's nothing and cheerfully informs her that it's time to head back to earth. As everyone left the ARK, Sonic turns back, waving goodbye to the fallen Shadow in a pensive and solemn tone.]]
* StoryArc: This is the first game in the ''Sonic'' series to deal with the story of Shadow. It was later continued in ''VideoGame/SonicHeroes'' and finished in ''VideoGame/ShadowTheHedgehog''.
* {{Stripperiffic}}: [[http://images3.wikia.nocookie.net/sonic/images/4/41/Rouge_18.png Rouge's alternate outfit in 2P-Mode]].
* SugarBowl: All of the Chao Gardens, where the most pressing issue is an empty stomach; even the Dark Garden, which looks like a haunted graveyard and has a pool of red liquid that may or may not be blood, is a pretty safe place for your cute little guys to reside.
* SuperDeformed: Curiously, Chaos Zero looks a lot "cuter" than he did in ''Sonic Adventure''.
* SympatheticPOV: The Last Story consolidates them.
* TakeMyHand: Rouge makes a misstep in the meteor field (wearing stilettos in space [[BrokenHeel doesn't seem as smart now]], does it?), almost plummeting into the lava. Knuckles grabs her and hoists her back up.
* ThemeTuneRap: Most of Knuckles' stages.
* TooGoodForThisSinfulEarth: [[spoiler:[[TearJerker Maria's last wish for Shadow was to make sure the people on Earth could have a chance to be happy.]]]]
* [[TheUglyGuysHotDaughter The Ugly Guy's Hot Cousin]]: Maria Robotnik. Eggman's related to '''''her'''''???
** [[MadScientistsBeautifulDaughter Mad Scientist Beautiful Granddaughter]]: Subverted. Prof. Gerald was rather sane before G.U.N. offed Maria. [[JumpedOffTheSlipperySlope Then he ran head first]] [[OmnicidalManiac into the "mad" part.]]
* UndergroundLevel: Aquatic Mine. Doubles as UnderTheSea and potentially DownTheDrain.
* ThisIsUnforgivable: Tails vows to never forgive Eggman for [[spoiler:blowing Sonic to smithereens, (or so he and Amy think)]]...
** Also Shadow's [[spoiler:initial]] thoughts about Maria's death.
* TimedMission: Several. [[spoiler:Finalhazard hits the Earth after 5 minutes, so you better beat it in that time.]] Metal Harbour has a small example, where landing on a platform by a rocket suddenly gives you just 15 seconds to grab onto it. To make matters worse, there is a second rung higher up, which can only be made with a couple of seconds to spare, and without it, an A-rank is extremely difficult. To round the list off, Security Hall gives you 5 minutes to complete it, and Green Forest and White Jungle give you 8 and 10 respectively. Also, every 4th mission is one.
** Every stage's fourth mission is one of these.
* TookALevelInBadass: Eggman, rather than relying on an army of MechaMooks in this game mostly does work on his, apart from aid from Shadow and Rogue, and he blows away entire armies in a machine that's nowhere nearly as intimidating as the huge machines he had in the last game, and he's FAR more competent than in any other appearance in the series.
* TubeTravel: In the Crazy Gadget stage.
* UltimateLifeForm: Shadow has the honor of [[TropeNamer naming the trope.]]
* {{Ungrateful B|astard}}itch: Rouge was this to Knuckles after he saved her from falling into the lava, but then Knuckles tells her [[IWasJustPassingThrough he was saving the pieces of the Master Emerald]].
* UpgradeVsPrototypeFight: This happens [[spoiler: in the final story where the two Ultimate Life Forms fight. Shadow, the perfected one, vs the Biolizard, the failed prototype.]]
* VideoGameCaringPotential: Chao. If you are nice enough to a Chao, it will have a big smile on its face and clap whenever your character picks it up. Beware, however, that being ''too'' nice to a Chao might result in the little guy getting a spoiled personality, making it throw tantrums even when only a little hungry. Balance is the key, but regardless, if the Chao is happy enough, it will reincarnate into a baby at the end of its life.
* VideoGameCrueltyPotential:
** Chao. You can hit it, throw it, put it in water and watch it flail if it doesn't know how to swim, make it starve, and all other sorts of things. Such abuse will result in the Chao crying a fountain of tears, blowing a raspberry at you, or if it's aggressive enough, it'll charge at you and futilely throw punches. If the chao is more sad/angry than happy, it ''won't'' reincarnate at the end of its life. With the introduction of Light and Dark Chao in this game, ''who'' is treating the Chao good or bad matters as much as ''how'' they're treated. So treating your Chao nicely with Shadow, Eggman, and Rouge will make them Dark as well as being cruel with the good guys will, and vice versa.
** Omochao is another source of cruelty potential as mentioned above, but even Chao ''lovers'' like to torture the thing. [[WhatMeasureIsANonHuman Then again, it is a robot that just looks like a Chao and is not an actual Chao]]...
*** That, and it's [[MostAnnoyingSound annoying as all get out]]. See StopHelpingMe above.
* VideoGameSettings:
** BigBoosHaunt: Pyramid Cave, Pumpkin Hill, Aquatic Mine, Death Chamber and Egg Quarters.
** BlackoutBasement: Lost Colony.
** BuildLikeAnEgyptian: Pyramid Cave, Death Chamber and Egg Quarters.
** DeathMountain: Wild Canyon, Pumpkin Hill and Sky Rail.
** EternalEngine: [[TropeNamer Eternal Engine]].
** FloatingContinent: Sky Rail.
** GraffitiTown: City Escape, Radical Highway and Mission Street.
** GravityScrew: Crazy Gadget and Mad Space.
** GreenHillZone: Wild Canyon, Dry Lagoon and [[spoiler: [[HundredPercentCompletion 3D]] [[VideoGame/SonicTheHedgehog1 Green]] [[TropeNamer Hill]] [[NostalgiaLevel Zone]]]]
** JungleJapes: Green Forest and White Jungle.
** NostalgiaLevel: [[spoiler: GreenHillZone]]
** PalmtreePanic: Dry Lagoon.
** RacingMiniGame: Route 101 and Route 280 (and the multiplayer sub-game as well).
** RemilitarizedZone: Metal Harbor and Weapons Bed.
** ShiftingSandLand: Hidden Base and Sand Ocean.
** SpaceZone: Crazy Gadget, Final Rush, Eternal Engine, Meteor Herd, Final Chase, Lost Colony, Cosmic Wall and Mad Space.
** TheAlcatraz: Prison Lane, Iron Gate and Security Hall.
** UndergroundLevel: Aquatic Mine.
* VillainousLegacy: Gerald Robotnik. The main conflict of the story is against Eggman, but it was Gerald's actions 50 years in the past that caused many of the problems in the game.
* VillainProtagonist: Eggman, Rouge, and Shadow in the Dark Story.
* WhenSheSmiles: Rouge is depicted of making seductive and devious expressions, but after Knuckles leaves after restoring the Master Emerald, she gives out a tender smile at him, marking a sign of her true feelings for Knuckles.
* WhiteGloves: It seems they are popular, as all six main characters use them.
* WingedHumanoid: Rouge.
* WoobieDestroyerOfWorlds:
** Gerald becomes somewhat sympathetic once you realize how he lost ''everything'' important to him. To see how far Gerald fell, just watch the cutscene in ''ShadowTheHedgehog'' where he instructs Shadow (via old video footage) to use the Eclipse Cannon ''for the good of humanity by destroying the Black Comet''. All it took was the death of Maria for Gerald to go insane and completely alter his motives.
** Shadow the Hedgehog also counts for this to a certain degree. The reason he's attempting to destroy humanity? Because he thought that his promise to Maria was for ''revenge''.
* WorldOfCardboardSpeech: Succinctly phrased during the endgame:
--> ''"What you see is what you get: Just a guy that loves adventure. I'm Sonic the Hedgehog!"''
* WorthyOpponent: Eggman displays a sudden spike in competence when he locks Sonic in a space pod and then fires it into space--and then blows it up for good measure. As he overlooks the explosion, Eggman solemnly declares Sonic an "admirable adversary."
** Shadow had a similar reaction: When witnessing Sonic's seeming death, Shadow says "Looks like he was simply an ordinary hedgehog after all" with a tinge of disappointment. Curiously both Eggman and Shadow are somewhat nonchalent, even amused when realising he survived, Shadow even directly telling him he managed to impress him.
* WouldHitAGirl: Knuckles had no qualms in attacking Rouge, who can hold on her own against him. However, he reluctantly apologizes for this after restoring the Master Emerald.
-->'''Rouge''': You call yourself a hunter, attacking a lady? Shame on you!\\
'''Knuckles''': What kind of lady goes around stealing gems anyway?!
* YouJustToldMe: Eggman pulls a magnificent one on Tails and Sonic when they come to rescue Amy.
--> '''Eggman:''' "You thought you could trick me with that fake emerald, didn't you?"
--> '''Tails:''' "So... how did you know it wasn't the real one?"
--> '''Sonic:''' "Tails!"
--> '''Eggman:''' "Because ''you just TOLD me, fox boy!''"
** [[JustForPun Meaning, of course, that Tails was outfoxed.]]
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->"C'mon, let's go home. To the planet as cool and blue as me!"