Sonic the Hedgehog 2 is the second game to be released in the Sonic series. This game introduced Sonic's faithful sidekick Miles "Tails" Prower to audiences. This is also the first Sonic game where Sonic can become Super Sonic by collecting all the Chaos Emeralds. It was the best selling Sonic game on the SEGA Mega Drive/Genesis, selling over six million copies worldwide after only six months of release. Like Sonic The Hedgehog, it also became a pack-in game for the console.
 Knuckles in Sonic 2
Slotting this game into Sonic & Knuckles unlocks Knuckles In Sonic 2. Knuckles The Echidna in Sonic 2 is a gimmick employed with the Lock-On Technology in Sonic & Knuckles. The gameplay is exactly the same as Sonic The Hedgehog 2, however, Sonic and Tails are replaced by Knuckles. Knuckles retains his glide and can reach to harder spots more easily. However, his jump is lower, making it harder to beat certain bosses, particularly the final boss.
The game has subsequently been ported to Microsoft's Xbox Live Arcade service, Virtual Console for Nintendo Wii and Playstation Network, aswell as included in several compilations:
- Sonic Compilation for SEGA Mega Drive/Genesis
- Sonic Jam for SEGA Saturn
- SEGA Smash Pack for SEGA Dreamcast
- Sonic Mega Collection for Nintendo Gamecube
- Sonic Mega Collection Plus for Nintendo Gamecube, Sony Playstation 2 and Microsoft Xbox
- Sega Genesis Collection/Sega Mega Drive Collection for Playstation 2 and PSP
- Sonic's Ultimate Genesis Collection/Sega Mega Drive Ultimate Collection for Sony Playstation Portable
- Sonic Classic Collection for Nintendo DS
 Game Storyline
taken from the US Sonic 2 manual
Find the Chaos Emeralds! Miles "Tails" Prower the fox can't sit still when Sonic's around. Ever since Miles was a baby fox, he's dreamed of being like Sonic. He loves to run after Sonic, waving his two tails behind him, trying to keep up with his hero! Mostly, Sonic lets him trail along. But sometimes, just to show off, Sonic explodes in a burst of super speed and leaves him behind. But Miles doesn't give up. He whirls his tails like a helicopter rotor and takes off flying until he catches up! All the animals call Miles by his nickname, "Tails", because of his two special tails. And one day they saw an astonishing feat... They were all together in the forest, watching Sonic perform. Sonic would run, spin and jump in his Super Spin Attack. Then "Tails" would whirl like a turbo engine and blast off in his Super Dash Attack. What a showoff! Suddenly, "Tails" just couldn't help himself. He took a running start, curled up his tails, and - whoosh - he was spinning like Sonic!
But now something frightening is happening. Sonic's friends are disappearing. In their place, nasty metal robots are popping up all over the island. The mad scientist Dr Robotnik is at it again! This time, Robotnik's planning a global disaster. He needs workers to create a doomsday machine that can take over the world. So he's trapping all the animals, turning them into robots, and forcing them to build his ultimate weapon, the Death Egg! Robotnik now rules the factories, refineries and cities! He's grabbed control of everything - except the 7 Chaos Emeralds. These magnificent gems are believed to hold exceptional powers. With them, Robotnik could have the entire world in his grasp. And he'd never let go! The Chaos Emeralds are buried somewhere on the island. Only one tough dude with spiky hair has the speed to find them first!
Help Sonic stop the devious scheme of the demented scientist! Spin like a speedball through space. Grab Power Sneakers and loop 'til you're dizzy. Twirl over twisting speedways and rocket through tunnels. Balance and blast across a bubbling ocean of oil! Find the Emeralds, free the animals, and squash Robotnik forever!
A split-screen multi-player mode was also included in the game, letting Sonic and Tails compete head to head. Four zones are playable in this mode, Emerald Hill, Casino Night, Mystic Cave and the Special Zone. There are no bosses. Players are marked on 5 criteria:
- Finish Time
- Rings (The largest total collected at any point in the act)
- Rings (The total collected at the point of finishing the act)
- Item Boxes (The number of item boxes collected)
- Emerald Hill Zone
- Chemical Plant Zone
- Aquatic Ruin Zone
- Casino Night Zone
- Hill Top Zone
- Mystic Cave Zone
- Oil Ocean Zone
- Metropolis Zone
- Sky Chase Zone
- Wing Fortress Zone
- Death Egg Zone
- Special Zone
- Drill Eggman
- Water Eggman
- Hammer Eggman
- Catcher Eggman
- Submarine Eggman
- Drill Eggman 2
- Submarine Eggman 2
- Flying Eggman
- Barrier Eggman
- Silver Sonic
- Death Egg Robot
- Power Sneakers
- Super Ring
- Robotnik Box - Multi-player Only
- Switch Box - Multi-player Only
- Sonic the Hedgehog 2 was the best-selling Sega Genesis/Mega Drive game of all time.
- The developers wanted to pay tribute to two of the biggest franchises in pop-culture from both the East and the West. From the East we received Super Sonic, which is a tribute to Dragonball Z's Super Saiyan characters. From the West we received the end level, the Death Egg, which is based off of Star Wars' Death Star.
- The game's level select code 19, 65, 09, 17 is actually Yuji Naka's birthday, the creator of the Sonic series. September 17th, 1965
- The game's debug code 1, 9, 9, 2, 1, 1, 2, 4 stands for November 24th, 1992, which is the US version's release date.
 Cheat Codes
These are cheat codes which can be accessed by inputting songs into the Sound Select screen. A + means the buttons must be held simultaneously.
 Zone Select
Play tunes 19, 65, 09, 17 on the options screen, A+Start on title screen.
 14 Continues
Play tunes 01, 01, 02, 04 on the options screen. An incorrect sound command is issued, causing OOZ music to continue playing until a reset.
 Super Sonic
Play tunes 04, 01, 02, 06 on the zone select sound test, an emerald sound triggers, select zone, hold A until Sonic appears.
 Debug Mode
Play tunes 01, 09, 09, 02, 01, 01, 02, 04 on the zone select sound test, a ring sound triggers, select zone, hold A until Sonic appears.
Music from the game features in the following CD soundtracks: