Sonic Adventure 2

Sonic Adventure 2 is a platform game developed by Sonic Team USA and published by Sega in 2001 as a part of the Sonic the Hedgehog series.

Sonic Adventure 2 is a sequel of Sonic Adventure. The next game is Sonic Heroes, which uses elements from this game. It was released in North America on June 5, 2001 and in Japan and Europe on June 23, 2001 to mark the 10th anniversary of the release of the original Sonic the Hedgehog. This game introduces two new playable characters, Shadow the Hedgehog and Rouge the Bat, and is also one of the few Sonic games to officially feature Doctor Eggman as a playable character. On December 10, 2001, a port of the game called Sonic Adventure 2 Battle was released onto the Nintendo GameCube in Japan, followed by North America on February 12, 2002 and Europe on May 3, 2002.

Single player
Gameplay takes place between two parallel storylines, the "Hero" story and the "Dark" story; the player has the option of advancing in either one or the other at any time. The "Hero" story featuring Sonic, Knuckles, Tails and the non-playable Amy, while the "Dark" story featuring Shadow, Rouge, and Doctor Eggman. Each hero character plays similarly to their respective dark character, and vice versa. Levels advance in order for each storyline, alternating between each of the playable characters.

Levels featuring Sonic or Shadow are designed in much the same way as they were in Sonic's levels in Sonic Adventure, wherein the player's primary objective is simply to get to the end of the level. Levels with Tails or Dr. Eggman allow the player to control a mechanized robot walker and generally blast their way to the end, much like E-102 Gamma's stages in Sonic Adventure. Knuckles and Rouge are required to scour their levels for shards of the Master Emerald (with the exception of 2 stages where they must find keys into Eggman's base and 1 stage where chaos emeralds are located), again, much like Sonic Adventure. Interspersed between the levels are various bosses, which one particular character must fight. The main story line can only be finished when both "Hero" and "Dark" story modes are finished, and an extra story feature is revealed where the player must use all the characters to win.

Within Action Stages, players collect rings and defeat enemies, with a timer counting the time spent within the level. At the end of each stage, the player is given a score based on the number or rings collected and time spent within the level. The more rings and less time, the higher the score is. The player is also given a rank-based performance, a letter grade that is either A, B, C, D, or E, with A being the highest and E being the lowest. Irrelevant to any other factors, an A Rank is automatically awarded to players that complete any score-ranked mission with all of the rings from that level in the player's possession.

There are five missions within each Action Stage; in order to obtain the second mission, the player must complete the first one, to unlock the third, the second mission must be finished, and so on. In order from first through fifth, the missions are to complete the level, collect 100 rings, find a "lost Chao" using the Mystic Melody upgrade, finish within a time limit, and complete a "Hard mode" version of the Action Stage.

Emblems are also given within the game; there are 180 Emblems in total. In order to gain all 180 Emblems, players must defeat every mission within every stage, achieve an A rank in all stages and missions, etc. After collecting all 180 Emblems the player unlocks an extra level 3-D Green Hill level. 3-D Green Hill is a remake of Green Hill Zone from the original Sonic the Hedgehog game.

Two-player mode
There are some characters that can only be played on two-player mode. These include, Amy Rose, Metal Sonic, Tikal the Echidna, Chaos, Chao and Dark Chao. Big the Cat is also playable in the Dreamcast version of the game (replaced by Dark Chao in Battle). However, using Action Replay these characters can be playable in single player mode.

A multitude of levels from single player are playable. The levels playable in two player mode are mostly the same as the normal game; Sonic, Shadow, Amy and Metal Sonic race, Tails, Eggman, Chao and Dark Chao(or Big) have a shootout, and Knuckles, Rouge, Tikal and Chaos hunt for emerald shards.

There is also another secret that is able to unlock on both Dreamcast and the Game Cube version. If you get an A rank on every character's missions (Game Cube Only), or beat every characters mission (Dreamcast Only) in one player mode you get a secret suit that you can only use in two player mode. These suits also look different in each version of the game, but Tails' and Knuckles' suits look the same in both (except Knuckles gets tribal marks with his suit in the Dreamcast version).

Reception
thumb|250px|left|Sonic Adventure 2 Trailer

Opinions of Sonic Adventure 2 are variable among both professional reviewers and fans of the Sonic series. At its initial release on the Dreamcast, Sonic Adventure 2 was the recipient of very positive reviews, averaging an 89% according to critic compiler Metacritic. However, the Nintendo GameCube port (Sonic Adventure 2 Battle) fared considerably worse in terms of reviews, despite having no single player gameplay changes from the Dreamcast version and only an 8-month gap between their releases.

To date, the game has done well with sales of 1.44 million units in North America alone, making it one of the GameCube's highest selling games, and it is still one of the most popular GameCube games. This game also made it to Player's Choice.

Hero Story:
It begins with a Military helicopter (Sigma-Alpha 2) flying over the city. "Hedgehog captured", the pilot said. Suddenly he starts shouting "Hedgehog is escaping! Repeat, hedgehog is escaping!" At that moment Sonic the Hedgehog jumped out of the helicopter, ripping off a piece of the wing to use as a snowboard, and then jumped off. After he destroys a Military Fighter, he encountered a near look-alike of himself named Shadow the Hedgehog who had stolen a Chaos Emerald from the bank a while earlier. Sonic realizes that the military are mistaking him for Shadow. Then Shadow uses the emerald to transport to a different location and Sonic is arrested.

At the same time Knuckles the Echidna and a mysterious character named Rouge the Bat are fighting over who owns the Master Emerald. Dr. Eggman tried to steal the Master Emerald, but Knuckles stopped him in his path by breaking the Master Emerald into pieces. Knuckles and Rouge had hunt for the pieces of the Master Emerald. Knuckles found the first three pieces in Wild Canyon.

The next day Miles "Tails" Prower came to Prison Island in search of Sonic, rescuing Amy Rose from Dr. Eggman in the process. Then Amy freed Sonic from his Prison Cell, and Sonic escaped on a missile. Knuckles left Wild Canyon, and headed for Pumpkin Hill. There he found three more pieces of the Master Emerald. Knuckles left Pumpkin Hill, and headed for the Aquatic Mine. Meanwhile, Sonic got weary, jumped off the missile, and landed on a small island in a vast jungle. There he confronted Shadow once again.

He soon discovered the jungle was going to explode and left just in time. When they got back Eggman was on T.V. everywhere and it was revealed he was being taped from the old space colony, ARK. Suddenly half of ARK came off, revealing a long pointer called the Eclipse Cannon which shot out a powerful beam and destroyed half of the moon. A timer on screen appeared saying 24 hours till the destruction of Earth. Later, Tails discovered Space Colony ARK and the massive power of the Eclipse Cannon. He had to find Sonic, tell the President, and escape the military all before it was too late. He eventually found Sonic, and escaped the military.

Meanwhile, Knuckles found the last three pieces he could find of the master emerald in the Aquatic Mine. He later popped out of a manhole beside Tails, who was talking to Sonic over a phone on loudspeaker, and Amy. Tails chased down the President, then he and Sonic told the President about the situation they were in. Sonic, Knuckles, Tails, and Amy then headed for Dr. Eggman's "secret" base inside the pyramid. Sonic broke through the security system. Knuckles then had to find three keys to get into the rocket room. Knuckles defeated King Boom Boo, the king of ghosts. After that, Dr. Eggman appeared and summoned the Egg Golem, which Sonic had to take care of. As soon as he was defeated, they blasted off in the rocket.

Knuckles sensed the pieces of the Master Emerald and in his excitement, he opened the cargo bay, and spun the ship, which crash landed into the ARK. Knuckles landed on a small planet and found the pieces he lost. He defeated Rouge and got the rest of the Emerald. Meanwhile, in Space Colony ARK, Tails was heading for the engine of the Eclipse Cannon. He destroyed the engine, it was up to Sonic now. Amy got kidnapped by Eggman and demanded the last emerald in exchange. Sonic, who had a fake chaos emerald, made it to the central control room. Sonic was shot out of an escape capsule that in the middle of space was going to explode.

All Tails, Amy and Eggman could see was a capsule blowing up so they thought Sonic was killed. Tails was so riled up, in a burst of anger he defeated the Doctor. Meanwhile, Knuckles (with the full master emerald) spotted Sonic coming out of a portal. Sonic told Knuckles how he used Chaos Control to save himself, and sped to the Eclipse Cannon. Sonic confronted Shadow one last time, and destroyed the Eclipse Cannon. Tails, grieving over Sonic's "death", looked out the window and saw Sonic at the tip of the cannon smiling.

Dark Story:
It begins with Dr. Eggman infiltrating Prison Island in search of the Ultimate Life Form A.K.A. Project:Shadow, a weapon created by his grandfather, Gerald Robotnik. He finds Shadow and using a Chaos Emerald, and the password M.A.R.I.A. and soon discovered that he was a hedgehog. So, he mistook Shadow the Hedgehog for his enemy Sonic the Hedgehog, and nearly fought him. Then Shadow proved himself by defeating the military guard fighter. After Shadow defeated him, he left, heading for Space Colony ARK and told Eggman to bring more chaos emeralds and meet him on the ARK.

Meanwhile, Rouge the Bat was fighting with Knuckles over who truly owned the Master Emerald. Dr. Eggman used this to his advantage, and took the Master Emerald. Knuckles stopped him by breaking the Master Emerald into pieces. Rouge and Knuckles had to hunt for the pieces of the Master Emerald. Rouge found three pieces in the Dry Lagoon.

Later, Dr. Eggman went to his base to check up on things (and watch the replay of the news). He found out that the G.U.N. robots were guarding his pyramid base. He destroyed them and went on inside. While he was watching the replay of the news, he discovered that Shadow had stolen a Chaos Emerald from the federal reserve bank yesterday (everyone mistaking him for Sonic). The scene changes to where Shadow was leaving the bank when he had a flashback of what happened on Space Colony ARK with him and his friend Maria Robotnik. He was speeding down the highway, destroying any robot that gets in his way.

He later saw Sonic, explained to Sonic who he was, and left. The next day, Rouge decided to infiltrate Dr. Eggman's base. To do so, she had to find three keys. Meanwhile, Dr. Eggman and Shadow were onboard the ARK. Shadow told Eggman about Space Colony ARK and the power of the Eclipse Cannon. He then put in the two Chaos Emeralds. They returned to the base at the time Rouge found the last key. Rouge persuaded her conditions to Eggman into helping her by giving him a Chaos Emerald, and telling him where three other emeralds were. Before the deal was closed, she introduced herself to Shadow.

Shadow, Dr. Eggman, and Rouge headed for Prison Island (where the three Chaos emeralds were). Dr. Eggman broke through the security system, and defeated Tails, who happened to be there. Rouge found the three Chaos emeralds (and defeated another Military Fighter). Shadow rushed through the jungle, planted the bomb, and found Sonic. It ended in a tie nethier won because Shadow had to escape the jungle before it blew up. So he grabbed Rouge, and warped onto the ARK.

Later Eggman was on T.V everywhere and it was revealed to all he was being taped from ARK. Half of the station came off which revealed a long pointer called the Eclipse Cannon which shot out a powerful beam, destroying half of the moon. Then, there was a timer on the screen saying 24 hours till the destruction of Earth. At the ARK, Rouge explained that she knew where the location of the last Chaos Emerald was, with Tails. Shadow and Rouge were trying to catch the Tornado (Tails' plane). Rouge couldn't catch up in her car, and Shadow couldn't catch them in Sky Rail. They headed back to the ARK to tell Eggman.

By this time, Knuckles had unlocked the entrance to Eggman's base, so Eggman summoned his Egg Golem. However, Sonic damaged the head of the golem too many times, causing it to turn on Eggman. Eggman had to destroy his Egg Golem to pass. A while later, he and Shadow (who were still on the pyramid) discovered that Sonic and his friends were on the ARK. Rouge soon discovered that Knuckles was on a small planet with the pieces of the Master Emerald. She found half of the pieces, then they fought. It was a draw and she gave the pieces to Knuckles.

Meanwhile, Eggman kidnapped Amy Rose. A while later Eggman discovered Tails, and Sonic went into the room he was in. Eggman shot Sonic out of an escape capsule which was going to explode, then at the last minute he snuck up behind them both and took the real emerald. Meanwhile, Shadow (who was shocked that Sonic survived) saw Sonic run up next to him. Sonic Kicked Shadow`s Ass one last time, and headed for the control room. Meanwhile, Eggman was putting in the last Chaos Emerald. While he was cheering over his "victory", a screen nearby was flashing WARNING!! WARNING!!

Last Story:
It continues from the Dark Story where the cannon is flashing WARNING!! WARNING!! Eggman is puzzled and doesn't know what to do but then he see's his grandfather Gerald Robotnik tied to a chair on the screen of the cannon.

Meanwhile it continues from the Hero Story where Sonic and Knuckles entered the room Amy and Tails were in but then they heard a rattle and suddenly Rouge came out of the blue. "You, you haven't give up yet?" Knuckles said. Rouge said that they are all doomed because the Space Colony Ark is heading towards Earth at a tremendous velocity. On T.V. everywhere, including the Ark, Gerald Robotnik is tied to a seat explaining how the Ark will crash into Earth and destroy it among the savage humans, with the power of all seven Chaos Emeralds.

Eggman comes in and Knuckles starts yelling at him, thinking that Eggman is behind all of this. But then Eggman gives Rouge his grandfather's diary and Rouge reads it out loud revealing that the professor went insane after his granddaughter Maria was killed. When the Space Colony ARK was shut down, Maria was killed in the process. Gerald went mad because he loved Maria so much. He wanted to curse all humans, so he made the Eclipse Cannon, and when having enough power (the 7 Chaos Emeralds) would be programmed to make ARK fall to Earth. It is revealed that Gerald made Shadow for good, to benefit man-kind but Space Colony ARK was destroyed, and as a result, so was project Ultimate Life Form A.K.A. Shadow. He was able to complete his research and finish Shadow, and he says that you may awaken it "if you wish to fill the world with destruction".

The gang have to stop the energy from the Chaos Emeralds to stop the Space Colony ARK from crashing with Earth. They then have a plan to stop the Chaos Emeralds with the Master Emerald. Amy finds Shadow and convinces him to help save the world. Shadow then has a flashback of Maria telling him the same, and launching him out of a shuttle down to Earth, so he wouldn't be destroyed on the ARK. He then takes off saying "I must keep my promise to Maria, and you."

Sonic and Knuckles are seen at a shrine that looks somewhat like the Shrine of the Chaos Emeralds, with the Chaos Emeralds there. When Sonic and Knuckles try to get closer to the Shrine to stop the Chaos Emeralds with the Master Emerald, Gerald's voice is heard again, and a snake/lizard like beast is awakened. They realize that this is the prototype of the Ultimate Life Form, Shadow being the finished product. Shadow appears and defeats the Biolizard (prototype of the Ultimate Life Form), while Sonic and Knuckles get to the shrine and find a space for the Master Emerald. Knuckles does the chant to negate the power of the Chaos Emeralds, and the Biolizard is transported to outer space. They hear Eggman's voice saying that the Biolizard is controlling the Space Colony ARK for a crash course to Earth.

Space Colony ARK, is no longer being powered by the Chaos Emeralds, but now by the Biolizard. Sonic and Shadow use the Chaos Emeralds to transform into Super Sonic and Super Shadow, respectively. They fight the Biolizard in outer space, and are about to unleash the final blow, when Maria's voice rings in Shadow's head again about giving people a chance to be happy. Both Sonic and Shadow use Chaos Control to warp the crashing space colony ARK, and the Biolizard back to its normal place, but his power was drained and he fell to Earth, realizing that he had fulfilled Maria's request in his "dying" moments.

Sonic Adventure 2 and Sonic Adventure differences
For Sonic and Shadow, instead of jumping on a capsule, the end of a stage is cleared when jumping into a giant ring with the word "GOAL" flashing in the middle. Adventure fields do not return in Sonic Adventure 2, but alternate stories come back. This game, though, does not have alternate stories for each character, and 3 characters are in one story, a lot like Sonic Heroes. There is a 2 Player Gameplay, unlike Sonic Adventure. When treasure hunting, the radar telling you how close you are no longer has the color blue as "closer but still not close enough." Tails does not roam around any more without a mechanical system, and always is in the Tornado in its walking-robot mode. Although when roaming around Chao World, both Eggman and Tails run around without their walking robots, and Tails can fly around again, without getting tired. A new action was added to Sonic and Shadow, the somersault. The music to the speed up shoes is the same musical writing, but different instruments.

Biolizard
Biolizard, the Prototype of Ultimate Life, is a creature which appears as the second to last, and final, boss; it is also seen briefly in a flashback in Shadow the Hedgehog. The Biolizard appears as a giant and alien looking lizard with a life support system on its back with tubes running down its neck to its head. According to Sonic X, the Biolizard is 85 meters long, 30 meters wide, 19.5 meters tall, and weighs 87.5 tons. The massive creature can either attack by trying to bite its enemies with crushing jaws, or attempting to hit them with its tail. Biolizard can also generate large black orbs from its mouth, create smaller, but extremely numerous, pink egg-like orbs that it can shoot at a target and manipulate gravity. Additionally, as a product of Project Shadow, the creature can use Chaos Control.

The Biolizard was an earlier version of "Project Shadow", a government project run by Professor Gerald Robotnik that was intended to create an "Ultimate Lifeform" as a first step towards humanity discovering the secret of immortality. Due to the experiments, it later needed a life support system. While the Biolizard was successful in the way that it was could regenerate and restore itself, and could self-reproduce, it was also unruly and dangerous. It was locked away when Gerald, with the aid of the alien Black Doom, produced a more advanced being: Shadow the Hedgehog. The military, on Earth, began to worry and fear about what Robotnik was building on the ARK. When GUN came to Space Colony ARK in order to put a stop to Professor Gerald's plans, they found the Biolizard and captured it. It didn't go without a fight, however, and it killed almost all of the GUN soldiers.

The Biolizard remained encapsulated aboard the ARK until Doctor Eggman placed the seven Chaos Emeralds into the Eclipse Cannon. This initiated a hidden program by Gerald, that would use the Emeralds to power the ARK into a doomsday causing collision with the planet below. The program released the Biolizard to defend the Armageddon plan from tampering by the combined forces of Eggman, Sonic the Hedgehog and friends. But Amy Rose had convinced Shadow to help save the Earth, and he engaged and defeated the giant reptile in battle by damaging its Life Support System. Knuckles rushed in afterwards and used the Master Emerald to negate the power of the Chaos Emeralds, supposedly putting a halt to the collision course. However, the Biolizard then used Chaos Control to teleport outside and fuse with the space station itself, becoming the Finalhazard. Its body mounted on the eclipse cannon, it continued the rush towards Earth by pulling it there itself. As Finalhazard it attacks with the pink orbs and firing out energy beams from its damaged Life Support System. It was, however, weakened by the loss of its Life Support System, revealing slight weak points on its body, and was killed by the combined power of Sonic and Shadow in super form. Together, Sonic and Shadow then used Chaos Control to place the ARK back into orbit, ending the collision course and saving the planet. If an Action Replay code is used, it is easy to ignore the Finalhazard, and the screen will start to get red. This means it's entering the atmosphere. Sonic's friends and Eggman tell the player when the colony will enter the atmosphere.

King Boom Boo
King Boom Boo is the king of all ghosts. He has ghost powers, but he and his ghost minions can lose power because of the sun. If they are touched by the sun's light, they become weaker and open to attacks. When they're not in contact with sun light, they become stronger and gain powers. These powers include throwing plasma balls and shooting a plasma beam from his mouth. He will also attempt to bite you at close range. He was defeated by Knuckles at the Death Chamber in Sonic Adventure 2 as a boss. His name (and to some extent, his appearance) are reminiscent of Nintendo's King Boo.

He appears on an episode of Sonic X, haunting an old mansion with his minions but doesn't appear in series' adaption of this game.

Egg Golem
The Egg Golem is a boss character appearing in Sonic Adventure 2. After Knuckles the Echidna defeats King Boom Boo, Eggman appears and summons a giant animated statue called the Egg Golem to battle Sonic. To defeat the Egg Golem, Sonic must run to his back, jump across the platforms that stick out, and attack the Golem's control mechanism atop its head.

In the Dark Story, Sonic immediately jumps up and kicks the control mechanism, causing the Egg Golem to go haywire and attack Eggman. In order to defeat it, Eggman has to use his Volkan Cannon to destroy its internal power generators. Once all three of them are destroyed, the Egg Golem becomes disabled and sinks down into the quicksand.

According to an eyecatcher card from Sonic X, The Egg Golem is 57 Metres tall and weighs 250 tons. The Egg Golem fights by smashing its hands and head against the circular platform that Sonic or Eggman are standing on. It can also create an electrical field around itself to repel attacks, or spin its arms around itself to sweep enemies off the platform.

The Egg Golem also appeared in the Sonic X adaption of Sonic Adventure 2. It was remotely controlled by Bokkun who used it to fight Sonic and Knuckles. The two heroes had a hard time with the golem, but eventually Cream the Rabbit stole the remote control from Bokkun just after he took Agent Topaz hostage, and made the Egg Golem chase Bokkun into the desert. It later appeared standing on top of Doctor Eggman's pyramid During Super Sonic and Super Shadow's fight against the Finalhazard, with Bokkun standing on its head.

A similar character was also used in the game Sonic &amp; Knuckles as the first act boss in the Sandopolis Zone. Like the Egg Golem it was an animated statue, vulnerable only on its head, and although it was not named, it may have been a partial inspiration for the later character. It is also unknown if it was recycled from the scrapped Egg Golem-type boss in Sonic X-Treme.

Sonic Adventure 2: Battle
Sonic Adventure 2: Battle is the enhanced port for GameCube.

Version differences

 * A Black Market has been added to the Chao Kindergarten. It was originally a limited feature of the website.
 * Big the Cat's cameos have been removed from the stages. He is also replaced by a Dark Chao in the multi-player mode. Some of Big's cameos are still present in three cutscenes.
 * Amy Rose, Chao, Tikal, Metal Sonic, Dark Chao Walker and Chaos 0 are now available at the start of the multi-player mode and have their own movesets. The 2P Mode also has more stages and settings, and alternate costumes now give the character slightly different attributes.
 * Chao Karate has been added to the Chao Stadium. The A-Life system has also been slightly enhanced.
 * The unlockable costumes for Sonic, Shadow, Knuckles, Rouge, Tails and Eggman have changed somewhat.
 * The VMU game Chao Adventure 2 has been replaced by the Tiny Chao Garden, available via GBA connection.
 * The graphics have been touched up. The main characters have minor enhancements, but lighting effects and enemy models have been noticeably downgraded. Inexplicably, some of the writing on the mechs has vanished as well.
 * The intro is diffrent showing the six main characters instead of just showing outer space with the game's logo.
 * The title screen and the main menu screen are different.
 * Some posters in the stages have been changed.
 * In the GameCube version of the cutscene where Sonic and Shadow meet for the first time, the police officers' voices are cut off short and over lap each other. In the Dreamcast version of the cutscene, the police officers shout at Sonic in full sentences.
 * The Chao Gardens were a little bit bigger in Dreamcast version. Also the Dark Garden has a ramp leading up to another tomb stone, unlike the GameCube version.
 * The Dreamcast version had the "Download Event" mode where the player could download various events.
 * A Halloween and Christmas theme can be set for the background and outfits for the characters. This was removed from the Gamecube version.
 * The Knuckles segment of the final level level, Cannon's Core, is made easier due to boxes being placed in the areas where he get air bubbles. When Knuckles takes in an air bubble he sinks a few inches. In the original version, taking in air would make him sink and touch the hazardous ground and take damage or lose a life. Because of the boxes in the GameCube version, Knuckles can take in the air bubbles without getting hurt.

Advertisement
The Dreamcast version is known for its infamous commercial which shows a scientist approaching a hedgehog labeled "Good Hedgehog" and petting it. The camera then goes to a tank labeled "Bad Hedgehog" where a cow is being lowered in. Eating sounds could be heard along with screams from the cow until the screen goes back to the bad hedgehog burping (this is a parody of a scene from Jurassic Park). The GameCube version's advertisement shows several real life hedgehogs being trained to take on the roles of Sonic and Shadow in the game.

Soundtracks
3 original soundtracks were released for Sonic Adventure 2: The vocal album called "Sonic Adventure 2 Vocals Collection: Cuts Unleashed" the score called "Multi-Dimensional Sonic Adventure 2 Soundtrack" and in North America the "Sonic Adventure 2 Official Soundtrack" Additionally, one of the Major Theme Songs of this soundtrack made it into Sonic and The Black Knight.

Trivia

 * Sonic Adventure 2 is the only game where Sonic wears Soap shoes in order to promote the product and the new extreme sport, freestyle grinding, that they were made for. There were also many billboards, blimps, and benches in the game that advertised the shoes. Sonic himself wore a custom version of the Scorcher/Nitro Soap shoe, while Shadow wears a pair of custom Broadside Soap shoes, as grinding (or "soaping") debuted as an important new gameplay element.
 * Ever since grinding has been introduced in Sonic Adventure 2, almost every Sonic game after it has grinding as a core gameplay element as well.
 * In the DreamCast version, In the cutscene before the level City Escape, Sonic’s model has his original shoes when he escapes from the helicopter, but when he jumped off of the helicopter's wing he was somehow wearing the Soap shoes.
 * In the cutscene mentioned above, the pilot of the helicopter identifies himself in military talk as Sigma-Alpha 2, which translates from Greek as "SA2", the game's initials.
 * Shadow was originally going to die in the last story, but his reception from fans caused him to be brought back for Sonic Heroes.
 * There is some unused dialogue in the game, including some Omochao quotes.
 * Some of the deleted clips were brought back in the GameCube version, however, as an easter egg if Sonic or Shadow carries him to the goal ring.
 * The hovering enemies, the G.U.N. Beetles, look very similar to the Egg Flyer enemy of Sonic the Hedgehog (2006).
 * If you go to the Theme Select screen, rotate the Control Stick clockwise for a while until you hear a chime sound. You will see a picture of the President's Secretary and should then be able to select the Secretary's Theme.
 * Green Hill Zone's return as an unlockable stage in Sonic Adventure 2 marks its big comeback in recent Sonic games, as it had not been seen for several years. Also, the stage's background music is a remixed version of the original song, and when Sonic destroys an enemy (which are the first Badniks instead of G.U.N. robots), the same sound effects from the original game are played instead of the new sound effects from Sonic Adventure 2.
 * In the GameCube version, when pausing, press and hold the Y and X buttons and the Pause Menu will disappear, giving you a clear view of the screen.
 * In the Mad Space level for Rouge, there are two Easter Eggs. First, go under the starting platform to its base, and kick open the iron box where you will find a blue defense item container from the Dreamcast game Phantasy Star Online: Episode I & II. Also, go to the outlying platform with a circle of rings and two iron boxes. Kick open the nearest iron box and you will see a green medical/technique item container from the same aforementioned RPG. However, neither items do anything or have any significance to the level.
 * In the Chao Garden, there's a glitch that makes it possible to reuse an animal from the Action Stages multiple times on a single chao. While holding your animal, go as close to your chao as possible without giving it the animal. Then simply drop the animal in front of your chao and, if done correctly, the chao will not only do the level up animation, but its stats will go up as if you actually handed the animal to the chao, only now you can pick the animal up again. This can also be done with Chaos Drives and can be used to quickly raise your chao's stats. This glitch is present in both the Dreamcast and GameCube versions.
 * Also in the Chao Garden, one of the shows shown on the garden's little TV (achieved by winning all Challenge Races), features a big, mustached, orange cat (Robotnik) chasing a speedy, little blue mouse (Sonic). This is a spoof of the classic cartoon show, Tom &amp; Jerry.
 * In the first cutscene of the "Last Story" when Gerald Robotnik's message was sent around the world, in the area where Eggman had one of his hidden bases and also the place where the Arabs were seen (Jerusalem or just the Middle East), in the background something that greatly resembles the holy Islamic building (mosque) called the "Dome of the Rock" can be seen.
 * Tails wasn't originally planned to be in the game as a playable character but was added near the end of the game's production, which is why he's not shown in any trailers. Therefore, very few of Tails' levels had much to do with the story.
 * Shadow was originally going to be named "Terios" ('reflection of'), and Rouge was going to be "Nails" (in direct contrast to Knuckles).
 * In the both versions, the in-game screenshots appearing in the Tutorial and Credits are all from the Dreamcast version. While some noticeable differences such as the different-colored select button, the treasure hunting exclamation point and the controller graphic were changed, you can see there aren't any new GameCube screenshots due to some Dreamcast-only things appearing, such as the altered posters in the background of City Escape or the writing on the mechs (most clearly the Eggman insignia and "IVO" on the back vanished in the GameCube version, but it still exists in the screens). This is an oversight on the developers' part. A similar mistake occured in Sonic Adventure DX, in which one of the buttons in one of the character instructions was that of the Dreamcast version rather than the GameCube one.
 * Strangely, SA2 has three different versions of bats. The first is the anthropomorphic bat, Rouge. The second is the small animal bat, used for chao raising. And the third, is a more realistic bat, found flying in groups inside Death Chamber.
 * In the Metal Harbor stage, when reaching the missile section, a voice over will say "Missile launch in 10 seconds." In the Japanese version, he says the same thing and it's still in English.
 * In the Dark Story, Sonic will jump and kick the Egg Golem in the head. While doing this, he says "Teriiiaaaaaa!!". In the Japanese version, Sonic says the same thing but it's longer.
 * In the Chao Garden, some characters will say Japanese lines (mostly Tails and Eggman). Also, the chao in the Chao Daycare sing songs in Japanese.
 * Unlike most games, the characters go through the same stages, but at different times. For example, Shadow's Sky Rail stage is Knuckles' Pumpkin Hill stage during the day. (Knuckles' Pumpkin Hill takes place at night)
 * In the original Dreamcast version of the game, if you insert the disk into a PC then special wallpapers will be available to download as an easter egg. As well as that, there is a list of main series Sonic Games prior to Sonic Adventure 2. It reads:

SERIES TITLE:

SONIC the Hedgehog ,1991 SONIC the Hedgehog 2 ,1992 SONIC the Hedgehog 3 ,1994 SONIC and KNUCKLES ,1994 SONIC JAM ,1997 SONIC Adventure (for Japan) ,1998 SONIC Adventure ,1999 SONIC Adventure International,1999 SONIC Adventure 2 The Trial ,2000