History Videogame / Sonic3AndKnuckles

*** The ''Origins Plus'' DLC adds perhaps the biggest change of the bunch: The ability to play as Amy Rose. For the most part, Amy is a MovesetClone of Sonic, having moves that act like Sonic's Insta-shield and Drop Dash (though Amy's version of the Insta-shield, which has her spin her hammer has a much larger and longer-lasting hitbox than Sonic's does and can be used even while transformed or using a shield), and unlike in any past appearance, she can actually turn Super and Hyper. Hyper Amy has a unique hammer throw attack that may be inspired by a similar move Amy can perform in ''VideoGame/SonicTheFighters'', though this is far less useful than the abilities of the other three Hyper forms, making it AwesomeButImpractical in comparison (Amy doesn't really need a projectile attack when ''she's already invulnerable from turning Hyper to begin with, and it's not automatic like Super/Hyper Tails' flickies).

** Unique to ''Origins Plus'', Amy will sway left and right on one foot. If doing nothing for several seconds, she'll clasp her hands to the side of her head and look skywards, presumably daydreaming (while still moving her right foot from the earlier animation), which is shared with the other three games.

*** The ''Origins Plus'' DLC adds perhaps the biggest change of the bunch: The ability to play as Amy Rose. For the most part, Amy is a MovesetClone of Sonic, having moves that act like Sonic's Insta-shield and Drop Dash (though Amy's version of the Insta-shield, which has her spin her hammer has a much larger and longer-lasting hitbox than Sonic's does and can be used even while transformed or using a shield), and unlike in any past appearance, she can actually turn Super and Hyper. Hyper Amy has a unique hammer throw attack that may be inspired by a similar move Amy can perform in ''VideoGame/SonicTheFighters'', though this is far less useful than the abilities of the other three Hyper forms, making it AwesomeButImpractical in comparison (Amy doesn't really need a projectile attack when ''she's already invulnerable from turning Hyper to begin with, and it's not automatic like Super/Hyper Tails' flickies).

** Hyper Sonic, Hyper Knuckles, and Super/Hyper Tails are this in a nutshell, but for different reasons. It's an unbelievable pain to get them, requiring all 14 Emeralds across two whole games, and if you fail to get all the Chaos Emeralds in the ''Sonic 3'' portion, you're locked out of getting them. If you do manage to obtain all of them, however, you're granted access to Hyper Sonic, Hyper Knuckles, and Super Tails (Hyper Tails in the ''Origins'' remaster), who have their own set of moves and abilities. They also look awesome. But beware that when you activate this, you lose a ring per second.

* HardLevelsEasyBosses: If you play as Sonic, you don't have Tails's flight to trivialize all the platforming, but the Insta-Shield gives you a huge attack range, and gives you the ability to bypass protections that certain bosses possess.

* InfinityMinusOneSword: Super Sonic and Super Knuckles are invincible and can move incredibly fast, but pale in comparison to the Hyper forms. In ''Sonic Origins'', Tails can access his Super form with just the Chaos Emeralds, but can't use the Flickies that attack enemies for him.
* InfinityPlusOneSword:

** In addition to the usual Super Sonic, it's also possible to play as Super Knuckles. And if you collect ''all 14 Emeralds'' you can become Hyper Sonic, Hyper Knuckles, or Super Tails.

->''Sonic races through the green fields.''\\
''The sun races through a blue sky filled with white clouds.''\\
''The ways of his heart are much like the sun. Sonic runs and rests; the sun rises and sets.''\\
''Don't give up on the sun. Don't make the sun laugh at you.''
-->-- Words taken from Japanese cover of ''Sonic & Knuckles''.

** The "Blue Spheres" theme was originally written by Yoshiaki Kashima for the cancelled arcade game ''[[https://www.youtube.com/watch?v=KBrwppYG2fE SegaSonic Bros]]''. Since Kashima also wrote the sound driver for ''Sonic 3 & Knuckles'', he was able to reuse the track.
** The prototype tracks that were cut from the original Genesis game ended up getting rearranged twice to be used in place of the final Genesis tracks: first in ''Sonic & Knuckles Collection'', a PC port of the game, then again by Jun Senoue for the Retro Engine version included in ''Sonic Origins''.

* ReplacedTheThemeTune: If you have ''Sonic 3'' hooked up to the ''Sonic & Knuckles'' cart, its title theme is replaced by the one from ''Sonic & Knuckles''. Same goes for some of the music in the game itself (1-up theme, mini-boss theme, invincibility theme, & Knuckles' theme).

** The "Get Blue Spheres" theme was originally used in the cancelled arcade game ''[[https://www.youtube.com/watch?v=-NJaLx9k_k4 SegaSonic Bros]]''.

* DamnYouMuscleMemory: In most 2D platformers featuring GravityScrew, the "up" and "down" controls are reversed along with the gravity. Not so in the Death Egg Zone in this game. Interestingly, Yuji Naka claims that there was a survey held prior to the game's release about whether the controls should be reversed in those particular segments, and that the majority decided that they shouldn't be.

* FakeTrap: ZigZagged with the enemies in Marble Garden Zone that resemble spikes. Landing on the tips won't hurt you; you'll simply bounce off as if it's a springboard. However, the enemy does pop out to shoot bullets at you, and you can still take damage from touching it if you do so from the sides. Fortunately, spin-attacking into the sides of spikes will safely reveal if they're real spikes (you'll just stop harmlessly) or a fake-spike enemy (you'll destroy it).

* SpikesOfDoom: One enemy in Marble Garden Zone subverts this; it fires projectiles at you, but hitting the tips of the spikes merely bounces you off without any damage. This is double subverted, as this being an enemy, you will still take damage by running into the side of the spikes, something that doesn't happen with real spikes.

** One of the greatest discussions among fans concerning this game is trying to figure out which ''Sonic 3'' songs are re-purposed Music/MichaelJackson's songs. One of the rearranged songs that ''wasn't'' made by Jackson is [=IceCap=] Zone's theme, which is actually a slightly remixed version of a then-unreleased song from the music group The Jetzons called "Hard Times"; the band included Brad Buxer, who was a songwriter for Jackson and is credited among the game's composers.

''Sonic the Hedgehog 3'', originally released on February 2, 1994,[[note]]Groundhog Day, so the launch date was naturally referred to as "Hedgehog Day"[[/note]] covers Sonic's arrival at the [[FloatingContinent Floating Island]] and his journey to Launch Base Zone. As in ''Sonic 2'', players can control Sonic the Hedgehog, Miles "Tails" Prower, or both. Knuckles the Echidna, an eventual member of the series' PowerTrio, made his debut in this game as an antagonist. It was the first ''Sonic'' game to offer save files.

''Sonic the Hedgehog 3'', originally released on February 2, 1994 (Groundhog Day. Get it?), covers Sonic's arrival at the [[FloatingContinent Floating Island]] and his journey to Launch Base Zone. As in ''Sonic 2'', players can control Sonic the Hedgehog, Miles "Tails" Prower, or both. Knuckles the Echidna, an eventual member of the series' PowerTrio, made his debut in this game as an antagonist. It was the first ''Sonic'' game to offer save files.

''Sonic the Hedgehog 3'', originally released on February 2, 1994, covers Sonic's arrival at the [[FloatingContinent Floating Island]] and his journey to Launch Base Zone. As in ''Sonic 2'', players can control Sonic the Hedgehog, Miles "Tails" Prower, or both. Knuckles the Echidna, an eventual member of the series' PowerTrio, made his debut in this game as an antagonist. It was the first ''Sonic'' game to offer save files.

* BonusBoss: Under normal circumstances, Knuckles never fights Carnival Night Zone Act 2's Orb of Light boss and can just pop the capsule at the end of his path to finish the level. If his climbing abilities are used to scale the fan shaft leading up to where Sonic and Tails would fight the boss, Knuckles can find the Eggrobo piloting the machine in Eggman's place and fight it as a result.

* NoPronunciationGuide: Is it "Hydro City Zone" or "Hydrocity Zone?"[[note]]Rhymes with velocity.[[/note]] The original Japanese script points towards the former, but there are those who still go with the latter mainly because [[RuleOfCool it sounds cooler]]. The Official Sega Genesis ''Sonic 3'' Play Guide goes with "[[TakeAThirdOption HydroCity Zone]]".

* AnAxeToGrind: Hey Ho, the boss of Mushroom Hill Zone Act 1, chops blocks of wood at the player with his axe.

* {{Antepiece}}: Carnival Night Zone has one poorly thought-out example. During Act 2, the player can come across a barrel that can be swung up and down, eventually letting the player access a higher floor. Later, the game locks the player in a room with a similar barrel (known among the fanbase as the "Barrel of Doom"), which must be swung in the same way, so the player can access a lower floor. What's the issue here, besides the controls of the barrel not being obvious to the player? The first barrel, the antepiece, is completely optional, since the player can get upstairs using a character power or take another route entirely and never have to deal with the barrel or even know it exists (you can also propel yourself high enough with the barrel with well-timed jumps, the only action that gives immediate feedback); the Barrel of Doom, on the other hand, cannot be bypassed.

* {{Antepiece}}: Carnival Night Zone has one poorly thought-out example. During Act 2, the player can come across a barrel that can be swung up and down, eventually letting the player access a higher floor. Later, the game locks the player in a room with a similar barrel (known among the fanbase as the "Barrel of Doom"), which must be swung in the same way, so the player can access a lower floor. What's the issue here, besides the controls of the barrel not being obvious to the player? The first barrel, the antepiece, is completely optional, since the player can get upstairs using a character power or take another route entirely and never have to deal with the barrel or even know it exists; the Barrel of Doom, on the other hand, cannot be bypassed.

* FloatingContinent: The setting of the game, although it got knocked out of the sky by the Death Egg's crash landing prior to Sonic's arrival. It gets raised at the end of Sonic's story path and remains afloat throughout Knuckles's [[spoiler:until Mecha Sonic steals the Master Emerald, which causes the island to fall back to the sea if the player fails to get the good ending]].

** Assuming the player is playing the full locked-on game, they're likely to have visited Hidden Palace Zone at least once before reaching it in the story proper, by hopping into the flashing Giant Rings present from Mushroom Hill Zone on. Lava Reef Zone Act 2 uses the same music as HPZ, which may clue them in on the fact that it's related to it and immediately precedes it in the level order.

** Defeating Big Arm in the ''Sonic Origins'' remaster causes Eggman to crash into the hanging platform the boss fight takes place on, making it burn up and detach from the Death Egg, which then crashes on the Floating Island ''again''.[[note]]In the original version, regardless if both games were locked on or not, Eggman simply leaves and the platform burns up on its own.[[/notes]]

* MagikarpPower: While Sonic and Knuckles unlock their [[SuperMode super forms]] after getting 7 Emeralds, Tails doesn't unlock his until he collects all 14 Emeralds.[[note]]In ''Origins'', he has a proper Super form, and the original Super Tails is renamed to Hyper Tails.[[/note]] However, his Super Tails abilities (particularly the four Flickies who will attack any enemies or bosses in Tails's vicinity) are even more of a game breaker than Hyper Sonic or Hyper Knuckles when it comes to bosses, as they let you can literally kill almost every boss ''just by standing in one spot (since you're invincible) and letting the birds kill the boss for you''. When combined with Tails' IdleAnimation, this leads to an amusing case of EpicBattleBoredom.

* MagikarpPower:
** While Sonic and Knuckles unlock their [[SuperMode super forms]] after getting 7 Emeralds, Tails doesn't unlock his until he collects all 14 Emeralds. However, his Super Tails abilities (particularly the four birds who will attack any enemies or bosses in Tails's vicinity) are even more of a game breaker than Hyper Sonic or Hyper Knuckles when it comes to bosses, as they let you can literally kill almost every boss ''just by standing in one spot (since you're invincible) and letting the birds kill the boss for you''. When combined with Tails' IdleAnimation, this leads to an amusing case of EpicBattleBoredom.

* KingMook: The Big Icedus, faced at the end of IceCap Zone Act 1, is this to the Icedus/Star Pointers.

** Sonic's Super and Hyper forms use palette swaps of many of the sprites of his base form.