History VideoGame / SonicTheHedgehog2

* SpellMyNameWithAnS: It's Westside Island or West Side Island, depending on who you ask.

The sequel to the original ''[[VideoGame/SonicTheHedgehog1 Sonic the Hedgehog]]'', this game introduced Sonic's sidekick Tails, along with Sonic's Emerald-charged SuperForm. It is the second-best selling [[UsefulNotes/SegaGenesis Genesis/Mega Drive]] game of all time, selling over six million copies, only outsold by its predecessor's 15 million mark. However, most of ''Sonic 1''[='=]s sales came from being a pack-in to the Genesis, with 4 million selling standalone, so ''Sonic 2'' is technically the best-selling standalone game for the console.

In 2015, another remake was released for the UsefulNotes/Nintendo3DS titled ''3D Sonic the Hedgehog 2''. Developed by M2, it's the final game in their ''3D Classics'' series for the handheld. In addition to 3D-enhanced visuals, the game also comes with the ability to play either the International or Japanese versions, an optional screen filter which emulates the look of a CRT television, a stage select screen (previously available through a cheat code), the ability to record replays, a save state feature, and finally, a new "Ring Keep" mode which eases less experienced players in by starting each stage or life with 10 rings and only taking half of them if they get hit. In 2020, this version was also released on the UsefulNotes/NintendoSwitch under the "SEGA AGES" line, featuring most of the same content minus the 3D visuals, but adding extra features like Knuckles, the Drop Dash from ''Sonic Mania'', and leaderboards.

** ''VideoGame/Sonic2XL'', a very funny ([[NintendoHard and very hard]]) hack that makes Sonic fatter if you grab rings.

** Beginning the fight against the Death Egg Robot behind it, by running to the right edge of the screen before it rises fully, nullifies its infamous forward-facing attacks and tricky hitbox. The boss has no attacks while in motion, allowing the player to score hits via attacking its easy-to-hit jetpack, and can fight the entire boss this way by staying on the right-side quarter of the screen so that the boss upon landing from offscreen will remain facing away from the player. Its only counterattack in this method is two waves of bomb drops that can be easily memorized and avoided.

* DropTheHammer: The Tonkachi Eggman/Egg Hammer boss of Aquatic Ruin Zone wields a giant one.

* EasyLevelTrick: You can get four free hits in on Mecha Sonic right off the bat by just sitting in the spot where he lands and spin-dashing in place. You can then mop up by doing likewise in the center of the room while he skates from end to end, which damages him instead of you.

* DubInducedPlothole:

** The purple liquid in Chemical Plant Zone was supposed to be some polluted but harmless water, presenting no risk to the player outside of drowning. The American manual claimed that it was a toxic liquid called "Mega Mack" and tried to pass its effect off [[AmericanKirbyIsHardcore as poisoning the player character instead of drowning him.]] Which of course brings the question of why simply jumping out the substance nullifies the poison.

** Unlike games from ''VideoGame/SonicChaos'' onward, you can't fly while playing as Tails (except in the 2013 remake).

* CharacterSelectForcing: Downplayed, but when playing alone, the default "Sonic and Tails" option is a little more difficult than playing either of them alone. In the Special Stages, you need more rings to succeed, and the computer Tails is very unlikely to make up the difference. It's also possible to put Tails in front in these stages, which is not good. Outside of Special Stages, Tails is liable to hit Eggman at the worst possible time, causing Sonic to go through him, which is particularly deadly in the Chemical Plant Zone encounter. Also, Tails Alone isn't quite as good as Sonic Alone in the original version, since he doesn't have a super form and doesn't have the flying ability to make up for it (except in the 2013 remake).

For while these two are meeting, [[BigBad Dr. Eggman]], [[IHaveManyNames a.k.a. Dr. Robotnik]], has begun operations on the other side of the island, managing to covertly produce a new generation of Badniks. He's arrived on Westside Island after becoming privy to legends that tell of a lost seventh Chaos Emerald -- and not long after, realizing that it and the other Emeralds had made Westside's depths their new hiding place after his defeat on South Island. Using the Emeralds' combined power, he hopes to complete his personalized space station, the Death Egg. After learning about the doctor's mad plan, Sonic and Tails team up to stop him.

* SpiritualSuccessor: Several levels follow the same themes as those in the first game:
** Emerald Hill Zone is this for Green Hill Zone.
** Aquatic Ruin Zone is this for Labyrinth Zone, due to its use of water and ruins, but is somewhat easier since the high route is fully above the water.
** Casino Night Zone is a development on Spring Yard Zone's "pinball machine" theme, to the extent that it ended up being one of the most influential levels, while all vestiges of Spring Yard were dropped.
** Hill Top Zone is one for Marble Zone, having the same general color scheme and focus on underground areas filled with lava, though the two are distinguished by Hill Top's more open-air look and feel.
** Metropolis Zone is for Scrap Brain Zone. Both are an EternalEngine, green in color, etc. This was so noticeable that some fans who first played ''Sonic 2'' for the first time were subject to YourPrincessIsInAnotherCastle when they found out it wasn't in fact the final Zone.

* DevelopersForesight: In the 2013 remake, [[spoiler:Knuckles' eyes won't peek out of the bushes in the GoldenEnding if you beat the game as him]].

* AdaptationalEarlyAppearance: Locking this game on to ''[[VideoGame/Sonic3AndKnuckles Sonic & Knuckles]]'' lets you play as Knuckles in this game's levels, when he originally appeared in ''Sonic 3''. If you don't consider the timeline order (which places this game after ''[[VideoGame/SonicTheHedgehogCD Sonic CD]]'') and only look at the games' original release order (before ''Sonic CD''), then you could say ''Sonic Origins Plus'' adding Amy Rose as a playable character also counts.

* AdaptationalEarlyAppearance: Locking this game on to ''[[VideoGame/Sonic3AndKnuckles Sonic & Knuckles]]'' lets you play as Knuckles in this game's levels, when he originally appeared in ''Sonic 3''. If you don't consider the timeline order (which places this game after ''[[VideoGame/SonicTheHedgehogCD Sonic CD]]'') and only look at the games' original release order (before ''Sonic CD''), then you could also say ''Sonic Origins Plus'' adding Amy Rose as a playable character also counts.

* AdaptationalEarlyAppearance: Locking this game on to ''[[VideoGame/Sonic3AndKnuckles Sonic & Knuckles]] lets you play as Knuckles in this game's levels, when he originally appeared in ''Sonic 3''. If you don't consider the timeline order (which places this game after ''[[VideoGame/SonicTheHedgehogCD Sonic CD]]'') and only look at the games' original release order (before ''Sonic CD''), then you could also say ''Sonic Origins Plus'' adding Amy Rose as a playable character also counts.

* BonusBoss: [[spoiler:Featured in the 2013 remake's Hidden Palace Zone, in place of the Mystic Cave Zone boss during gameplay.]]