Sonic Adventure 2

Sonic Adventure 2 is an action-adventure platformer game released by Team USA and published by Sega. It was released for the Dreamcast and is the last Sonic game released for a Sega console. Later, a port for the GameCube was made, and it was called Sonic Adventure 2 Battle, released on the same year with new content. The game had sold 1.44 million copies and was re-released in HD with content from Battle as DLC for Playstation Network, Xbox Live Arcade and Steam.

Story
The game has two modes for story, Hero and Dark. The hero mode follows Sonic, Tails, and Knuckles in an effort to save the world. The Dark Mode follows Shadow The Hedgehog, Rouge The Bat, and Dr.Eggman, as they try to conquer the world. After learning of a secret weapon from the diary of his late grandfather Prof. Gerald Robotnik, Eggman infiltrates a high-security G.U.N. facility in search of it. This weapon, a black hedgehog and self-proclaimed "Ultimate Life Form" named Shadow, offers to help Eggman take over the world, telling him to rendezvous at the abandoned Space Colony ARK with more Chaos Emeralds. Shadow then goes to Central City, where he steals an Emerald and ends up running into G.U.N. soldiers. He experiences a flashback to the death of a girl named Maria, begging him to fulfill an unspecified promise, which he interprets as a promise for revenge. He then blasts through the military forces and ends up confronting Sonic, who the military had mistaken for Shadow. After a brief confrontation, Shadow escapes and G.U.N. captures Sonic. Meanwhile, Knuckles confronts both Rouge and Eggman, who each attempt to steal the Master Emerald. Knuckles shatters the Emerald to prevent this, then proceeds to search for the scattered shards. While Rouge intends to collect the shards for personal benefit, she must also accomplish a mission for the government to spy on Eggman. This mission leads her to Eggman's base, and eventually the ARK. On board, Shadow reveals to Eggman a superweapon called the Eclipse Cannon, also created by Prof. Gerald, and relays his plan: use the Chaos Emeralds to charge the Eclipse Cannon, and utilize its destructive power to take over the world. Rouge then appears and joins the two in their search for the Emeralds.

Tails and Amy infiltrate G.U.N.'s island base and rescue Sonic while Eggman, Shadow, and Rouge collect three Emeralds on the island. Eggman then broadcasts his threats across the world and demonstrates the cannon's power by destroying half of the Moon. Sonic and company use their Emerald to track down the other six, with Knuckles coming along as well. Together, the group infiltrate Eggman's base, boarding his shuttle as it launches into space. Knuckles' Emerald shards are spilled along the way, and he leaves to collect them. He encounters and fights Rouge again, but after he saves her from falling into a lava pit, she nonchalantly surrenders her shards and Knuckles restores the Master Emerald.

Aboard the ARK, Tails reveals that he has created a counterfeit Chaos Emerald designed to reverse the energy fields of the real ones. However, when Sonic goes to place the fake Emerald into the Cannon, Eggman announces that he has captured Tails and Amy, forcing him to go back and rescue them. Sonic tries to trick Eggman with the fake, but Eggman traps and jettisons him in an escape pod rigged with explosives. Using the fake, Sonic manages to perform the "Chaos Control" technique and escape, but Tails, thinking Sonic is dead, fights and defeats Eggman. Shadow is sent to intercept Sonic before he destroys the Eclipse Cannon, but does not succeed.

After being defeated by Tails, Eggman manages to sneak away with an Emerald and goes to put it in the Eclipse Cannon. However, when he attempts to fire the cannon at full power, the ARK begins to fall toward Earth, and a recorded message from Gerald Robotnik is broadcast worldwide: he programmed the ARK to collide with Earth and destroy it, as revenge against humanity. It is also revealed in his diary that this hatred began when the government condemned his research and killed numerous colleagues, including his granddaughter Maria, when attempting to shut the ARK down. Eggman determines that the Emeralds' energy is causing the ARK to plummet, and everyone works together to get to the cannon's core and neutralize the energy.

Shadow refuses to participate, but Amy pleads for his help, reminding him of Maria's true request: for him to help mankind. Realizing this, he catches up with Sonic and Knuckles in the core, where they encounter the Biolizard, a prototype of the Ultimate Life Form. Shadow temporarily defeats it, allowing Knuckles to deactivate the Chaos Emeralds using the Master Emerald. However, the Biolizard uses Chaos Control to fuse with the cannon, becoming the Finalhazard and continuing the ARK's collision course. Using the power of the Chaos Emeralds, Sonic and Shadow transform into their super forms and defeat the Finalhazard, then use Chaos Control to teleport the ARK back into a stable orbit around Earth. However, the process depletes Shadow's energy and he plummets to Earth, content that he has fulfilled his promise to Maria, and is presumed dead. As the humans back on Earth celebrate, the two teams reflect on the events that have transpired, and as they leave the station, Sonic bids a final farewell to Shadow.

Gameplay
Sonic and Shadow maintain their speedy aspects and give a fast paced gameplay for levels based on platforming. Both of them have a homing attack they can use to take down enemy robots made by Eggman and G.U.N, and they can grind on rails. Eggman and Tail's levels are much more slower paced, and plays on a multi-directional shooting gameplay. They both have mechs which they can use to hover, jump short heights, and attack enemies. Knuckles' and Rouge's levels are wide-open and spread-out with action-adventure gameplay, and involve treasure hunting: in each level, they must find three shards of the Master Emerald. Their search is guided by radar and puzzle-based clues given by harmless robots. Knuckles and Rouge can glide, defeat enemies with punches and kicks, and scale walls, as well as digging into them to find power-ups.

The game has a health system which requires rings. When the player gets hit, while having rings, will take damage. If the player has no rings and gets hit, he will lose a life. If the player loses all his lives, he will be sent to the game over screen. The player may collect upgrades for the character, which can be found in levels. Sonic and Shadow find an upgrade that allows them to bounce up and down and reach higher areas, Tails and Eggman find an upgrade that raises the radius of their attack, and Knuckles and Rouge find one that gives them powerful kicks that can break certain containers. Other than the two main campaigns, the player can also raise a Chao in a virtual pet format. The Chao posesses five stat attributes, Swim, Fly, Run, Power, and Stamina. The Chao also have an alignment meter, which shows if they are in a good alignment, or Dark Alignment. They hatch from eggs, and with Chaos Drives, you can increase their stats. They can do karate and do racing minigames. Their alignment gradually changes based on their affection to the characters, for example, a Chao that likes Shadow will gradually become more Dark. Playing with Chao and giving them animals increases affection, and when a Chao becomes fully Hero or Dark, it will take on that form permanently. Chao eventually die, but if they received enough affection during their lives, they will reincarnate.

The game also has 180 emblems, which are earned from certain tasks. There are five missions in each level, and while the first is required to continue on during the campaign, other missions include completing a harder version of a level and collecting 100 rings. The player can gain emblems from missions, but can also gain them on tasks relating to Chao raising.

Hero Team
Sonic The Hedgehog - He is the main protagonist of the game, and is the rival of Shadow the Hedgehog. Along with Shadow, he has a super form which can be achieved when all seven Chaos Emeralds are collected.

Miles "Tails" Prower - Sonic's best friend, he is the brains of the team and fights with a Mech. He is the rival of Eggman.

Knuckles The Echidna - He is one of Sonic's many rivals, and the guardian of the Master Emerald. He is the rival of Rouge The Bat.

Dark Team
Shadow The Hedgehog - The "Ultimate Life Form", he is an amnesiac and tries to complete a promise he made to Maria. His rival is Sonic The Hedgehog.

Rouge The Bat - A thief among women, she teams with Eggman to conquer the world. Her rival is Knuckles the Echidna.

Dr.Eggman - The main Antagonist of the game, he is an evil scientist bent on conquering the world, trying to defeat Sonic and friends. His rival is Tails.

Trivia

 * Sonic Generations, released in 2011, contains elements that were in Adventure 2, including a remake of the City Escape level and remake of the Radical Highway stage in the Nintendo 3DS version. Shadow also appears in the game as a boss character, and the BioLizard is also a boss in the 3DS version.
 * Amy Rose and Tikal are playable, but not in the main story. Tikal is playable in the treasue hunting mini game, while Amy Rose is playable in the on-the-foot racing levels.
 * Shadow and Rouge had become so popular, that they ended up becoming recurring characters for other games in the Sonic Series, including Sonic Heroes.