Two years after Sonic Adventure brought Sega's mascot back to the forefront of the company, Sonic Team released its sequel, Sonic Adventure 2. Boasting vastly improved visuals, a rock-solid 60 frames-per-second framerate, it streamlined and expanded many of the conventions introduced in the original Sonic Adventure. For example, rather than the extended charge-up time required to execute Sonic's "Light Speed Dash" in Sonic Adventure, Sonic Adventure 2 shortened the name to "Light Dash" and had it instantly accessible at the touch of a button. Rather than have Sonic's homing attack lock on to anything near him (even objects behind him), Sonic Adventure 2's homing attack requires players to point Sonic in the general direction of the object they wanted to strike. The ''adventure fields'' hub stages of Sonic Adventure were also removed entirely, putting the focus squarely on action stages just as Sonic The Hedgehog, Sonic The Hedgehog 2, Sonic The Hedgehog 3, and Sonic & Knuckles did. This formula would later be repeated in Sonic Heroes and Shadow The Hedgehog.
Characters new to the Sonic series were the jewel thief Rouge the Bat and revenge-obsessed Shadow the Hedgehog, whom the game's story conveys as being notoriously similar in appearance to Sonic. (In the story, multiple characters and seemingly the entire human populace mistake him for Sonic.) Returning to the roster is Sonic, Tails, and Knuckles. The recurring villain of the Sonic series, Doctor Eggman, of course returned, but surprisingly, in Sonic Adventure 2 he made his debut appearance as a player-controlled character. In total this brings the number of playable characters up to six, just as Sonic Adventure had six playable characters. However, rather than having six separate storylines that cross paths, Sonic Adventure 2 divides things up by teams -- the "Hero" team, where the good guys (Sonic, Tails and Knuckles) reside, and the "Dark" team, home to the bad guys (Shadow, Eggman, and Rouge). Furthermore, whereas the six characters in Sonic Adventure were each more or less unique from each other, in Sonic Adventure 2, each character play style and abilities are for all intents and purposes completely identical to that character's rival. (This is most likely to keep the 2-player versus mode fair.) In this sense, Sonic Adventure 2 has only 3 unique characters, Sonic/Shadow being one, Knuckles/Rouge being another, and Tails/Eggman being the third.
Therefore, Sonic Adventure 2 contains only three gameplay types - (not counting the driving stages, of which there are only two) - fueling the "Rivals" aspect of the game. Sonic and Shadow are "Speed" type characters, and the majority of their levels are high-speed action platforming stages. Tails and Eggman, both piloting mechanized walking armor, are "Shooting" type characters, and are essentially Sonic Adventure 2's version of E-102 Gamma's gameplay from the first Sonic Adventure. Finally, Knuckles and Rouge are "Hunting" characters, in a reprisal of Knuckles' emerald-hunting gameplay from the first Sonic Adventure, in which the player must rely on a hot-and-cold radar system that alerts you whenever an emerald shard is nearby, and changes color as the distance between you and the emerald increases or decreases.
Not present in Sonic Adventure 2 are the free-roaming "Adventure Field" hub worlds from Sonic Adventure. Instead, the game falls back on the traditional linear progression and gameplay-only focus of the classic Sega Genesis Sonic titles. This also gives the narrative a fast-paced feel while it follows multiple ongoing events at once. Cutscenes often bookend levels and boss encounters, and the story frequently jumps around from character to character; in one level you may play as Sonic as he zips through a dense jungle, whereas in the next level you will play as Knuckles as he hunts for emerald pieces in haunted mountains.
Proper multiplayer gameplay finally makes a return to the franchise after nearly 7 years of absence, playing off of the rivals aspect: Two players can play race each other to the end goal in each stage as Sonic and Shadow, race each other to find three Emerald Shards as Knuckles and Rouge, and as Tails and Eggman, in their robot walkers, shoot it out in one of several small arenas, with the objective being to deplete the other's life bar.
After finishing the game, the player can re-visit any story event in the game via a DVD-style scene selection menu, or play any of the stages themselves by choosing one in the stage select mode. The player is also challenged to earn A-ranks on each stage by performing well in them. Each stage has 4 additional missions in addition to the default one, with each mission having its own A rank threshold to achieve by getting a good enough time or score.
The plot begins with Doctor Eggman infiltrating a military base which had since 50 years prior been hiding his grandfather's greatest invention, Project Shadow. Eggman doesn't know the full details of Project Shadow, but expects it to be some sort of weapon. What he finds instead is a black hedgehog, claiming his name is Shadow. Now free, Shadow promises to lend Doctor Eggman his aid - but that Eggman must first meet Shadow on the Space Colony ARK.
A week later, Sonic the Hedgehog finds himself on the run from the Military Organization, G.U.N (Guardian Unit of Nations), who have suddenly claimed that Sonic is a dangerous criminal. Unaware of what is going on, Sonic escapes and attempts to avoid capture when he encounters Shadow the Hedgehog, who is in the middle of stealing a Chaos Emerald. Putting two and two together, Sonic assumes the Military is mistaking Shadow for Sonic (and vice-versa), and that this "fake" Hedgehog is the reason Sonic is in so much trouble. Before Sonic can engage Shadow in battle, however, Shadow vanishes in to thin air using a power called "Chaos Control", leaving Sonic confused and quickly surrounded by dozens of fully-armed G.U.N soldiers.
Once again captured, Sonic is later freed from a prison cell by Amy Rose. Them together with Tails and Knuckles, they attempt to seek out Dr. Eggman and Shadow the Hedgehog in a race against time, while evading the military.
After Sonic Adventure 2 hit retail, SonicTeam published the Official Sonic Adventure 2 Strategy Guide in Japan, which contained "The Last Report on Project Shadow", written by the in-game character Rouge the Bat, in an effort to uncover the mystery of who - or what Shadow is, and where he came from. A summary of the report follows:
50 years ago, the current President of Nations contracted Professor Gerald Robotnik to research the feasability of immortality. Gerald initially refused to be involved, comparing it to to playing God. But when his niece, Maria Robotnik, contracted the terminal disease NIDS (Neuro-Immuno Deficiency Syndrome), Gerald reconsidered the project in the hopes that he could find a cure and save her life. The classified "Project Shadow" was launched on the Space Colony ARK where Gerald's science team would not be disturbed, and there they began researching the mysteries of the Chaos Emeralds and how they effected living tissue.
One experiment, designed to accelerate the rate of cell regeneration seen in some species of lizards, turned disastrous - the "Biolizard" subject grew ten times its normal size and became violent, killing several scientists before being contained. When the Military Organization G.U.N learned of this incident, they sprung in to action in order to shut down Project Shadow (violently, if necessary) before any further lives were lost. When they arrived aboard the ARK, Professor Gerald was already putting the finishing touches on what he called the "Ultimate Life-form": an immortal black hedgehog that could harness the energies of the Chaos Emeralds, named after the project he was born from - Shadow. Not knowing what the military would do with a creature like Shadow, Gerald entrusted Maria to take him to an escape pod and head down to the planet below where they would be safe.
They were intercepted by G.U.N soldiers, who, in an effort to kill Shadow, accidentally shot Maria instead. With her last dying breath, she sealed Shadow in the escape pod and ejected him to earth. When Professor Gerald heard the news of his niece's death, he flew in to rage and despair; the very project he wanted to use to save her life ended up being the instrument of her demise. Before being captured by G.U.N and sentenced to death for the Biolizard incident on the Space Colony ARK, Professor Gerald gave Shadow strict instructions to carry out revenge for what happened to Maria. But, before that could happen, G.U.N imprisoned Shadow in suspended animation to ensure that the truth about what happened on the ARK was never revealed.
Below is a list of the stages in the game, listed in the order which they are played in the story mode.
- SONIC: City Escape
- KNUCKLES: Wild Canyon
- TAILS: Prison Lane
- SONIC: Metal Harbor
- SONIC: Green Forest
- KNUCKLES: Pumpkin Hill
- TAILS: Mission Street
- KNUCKLES: Aquatic Mine
- [ Driving Stage ]: Route 101
- TAILS: Hidden Base
- SONIC: Pyramid Cave
- KNUCKLES: Death Chamber
- TAILS: Eternal Engine
- KNUCKLES: Meteor Herd
- SONIC: Crazy Gadget
- SONIC: Final Rush
- EGGMAN: Iron Gate
- ROUGE: Dry Lagoon
- EGGMAN: Sand Ocean
- SHADOW: Radical Highway
- ROUGE: Egg Quarters
- EGGMAN: Lost Colony
- EGGMAN: Weapons Bed
- ROUGE: Security Hall
- SHADOW: White Jungle
- [ Driving Stage ]: Route 280
- SHADOW: Sky Rail
- ROUGE: Mad Space
- EGGMAN: Cosmic Wall
- SHADOW: Final Chase
''Sonic Adventure 2 Multi-Dimensional Soundtrack''
An official 2-disc soundtrack was released, containing almost all of the music from Sonic Adventure 2. The song list is as follows:
|1.||"SA2...Main Riff for "Sonic Adventure 2""||0:22|
|2.||"Event: Let's Make It!"||0:46|
|3.||"Escape from the City...for City Escape"||2:18|
|4.||"The Mad Convoy Race...for City Escape"||0:48|
|5.||"That's the Way I Like It...for Metal Harbor"||2:44|
|6.||"Can't Stop, So What!?...for Metal Harbor"||0:54|
|7.||"Won't Stop, Just Go!...for Green Forest"||2:28|
|8.||"Keys the Ruin...for Pyramid Cave"||3:27|
|9.||"Unstable World...for Crazy Gadget"||2:51|
|10.||"Highway in the Sky...for Final Rush"||2:59|
|11.||"Boss: -GUN- Mobile"||1:55|
|12.||"Advertise: SA2...in the Groove"||2:08|
|14.||"This Way Out...for Prison Lane"||3:11|
|15.||"Rumbling Highway...for Mission Street"||2:46|
|16.||"Chasing Drive...for Kart"||2:43|
|17.||"Down in the Base...for Hidden Base"||3:35|
|18.||"On the Edge...for Eternal Engine"||2:52|
|19.||"Advertise: SA2 ver. B"||0:27|
|20.||"Kick the Rock!...for Wild Canyon"||3:15|
|21.||"A Ghost's Pumpkin Soup...for Pumpkin Hill"||3:24|
|22.||"Dive Into the Mellow...for Aquatic Mine"||3:37|
|23.||"Deeper...for Death Chamber"||4:07|
|24.||"Space Trip Steps...for Meteor Herd"||3:31|
|25.||"Boss: Masters of the Desert"||2:05|
|27.||"Advertise: Prof. Omochao"||1:29|
|28.||"Chao Race Extended Mix [Chao's Doki Doki Banana Chips Run Mix]"||6:44|
|29.||"Chao Garden Extended Mix [Chao's Wack Wack Up & Down the Ground Mix]"||8:09|
|1.||"Vengeance is Mine...for Radical Highway"||2:32|
|2.||"Rhythm and Balance...for White Jungle"||2:28|
|3.||"Mr. Unsmiley...for Sky Rail"||1:50|
|4.||"The Supernatural...for Final Chase"||2:49|
|5.||"For True Story...for Sonic vs. Shadow"||2:31|
|7.||"Hey You! It's Time to Speed Up Again!!!"||0:27|
|8.||"Still Invincible...No Fear!"||0:56|
|9.||"Advertise: Rhythmic Passage"||1:07|
|10.||"Boss: Suitable Opponent"||1:59|
|11.||"Remember Me? - M.F.M....for Iron Gate"||2:20|
|12.||"Way to the Base...for Sand Ocean"||2:52|
|13.||"Trespasser...for Lost Colony"||2:25|
|14.||"Crush'em All...for Weapons Bed"||1:50|
|15.||"Soarin' Over the Space...for Cosmic Wall"||3:04|
|16.||"Event: 3 Black Noises"||5:20|
|17.||"Advertise: SA2 ver. C"||0:27|
|18.||"Event: Sonic vs. Shadow"||1:19|
|19.||"Bright Sound...for Dry Lagoon"||3:35|
|20.||"Lovely Gate 3...for Egg Quarters"||3:18|
|21.||"I'm a Spy...for Security Hall"||3:37|
|22.||"34° N, 12° E...for Mad Space"||3:33|
|23.||"Event: The Base"||1:53|
|24.||"Boss: Shut Up Faker!"||1:42|
|25.||"Scramble for the Core...for Cannon's Core ver. 1"||2:03|
|26.||"Cooperation...for Cannon's Core ver. 2"||1:59|
|27.||"Deep Inside of...for Cannon's Core ver. 3"||3:18|
|28.||"Supporting Me...for Biolizard"||3:29|
|30.||"Event: The Last Scene"||3:36|
|31.||"Live & Learn...Main Theme of "Sonic Adventure 2""||0:03|
''Cuts Unleashed: SA2 Vocal Collection''
This short, one-disc soundtrack focuses on just vocal tracks. The song list is as follows:
|1.||"It Doesn't Matter (Sonic's Theme)"||2:44|
|2.||"Escape From The City"||2:21|
|3.||"Believe In Myself (Tails' Theme)"||3:57|
|4.||"Unknown From M.E. (Knuckles' Theme)"||4:50|
|5.||"Fly In The Freedom (Rouge's Theme)"||4:55|
|6.||"Throw It All Away (Shadow's Theme)"||5:00|
|7.||"E.G.G.M.A.N. (Eggman's Theme)"||3:22|
|8.||"Live & Learn (Main Theme)"||4:32|
After Takashi Iizuka brought select members of Sonic Team to America to polish up the English release of the original Sonic Adventure, the team immediately began their first project as the U.S. branch of Sonic Team - Sonic Adventure 2. Taking inspiration from their Southern California location, Sonic Team decided to set SA2 in the fictional "Central City", featuring their own takes on San Francisco landmarks like the Golden Gate Bridge and more.
Throughout its development cycle, Sonic Adventure 2 changed rather dramatically. Early media and interviews with Yuji Naka point to there only being three playable characters initially: Sonic, Knuckles, and Eggman. After outcry from gamers wondering where certain franchise-staple characters were, Tails, Shadow, and Rouge were revealed to be playable. The fact that Tails, Shadow, and Rouge were possibly added to the roster later in development may help explain why over half the levels in the game recycle assets from other stages.
Other early preview material point to the game at one point having branching storyline pathways; one example given of this in effect was a scenario involving Sonic trapped, underwater, in a submarine. The player would be given one of two options: Make Sonic try to pilot the submarine to safety, or open the hatch and take his chances in the water (despite Sonic being unable to swim). Though scrapped for Sonic Adventure 2, branching storyline pathways were eventually introduced in Sonic Adventure 2 pseudo-sequel Shadow the Hedgehog; however neither Sonic Adventure 2 nor Shadow the Hedgehog contains any scene with a submarine in it.
Sonic Adventure 2 saw simultaneous world-wide release on June 23rd, 2001 - Sonic's 10th Anniversary. A special collectors edition of the game was produced, featuring a large blue case that contained the game, a music CD (featuring tracks spanning Sonic's 10 year history), a Sonic the Hedgehog Retrospective booklet, and a commemorative coin. Though originally intended to be limited edition, so many copies of the 10th Anniversary Edition were published that it is fairly easy to find one for relatively cheap.
- This is the last Sonic the Hedgehog game produced exclusively for Sega hardware. Near the end of the game's development cycle, Sega announced they would no longer be producing console hardware and were transitioning in to becoming a software-only company. One of the first cross-platform releases was a Nintendo Gamecube port of Sonic Adventure 2 entitled " Sonic Adventure 2: Battle". It contained more polished graphics, tweaked level designs, and an expanded multiplayer mode that added more playable characters such as Amy and Metal Sonic. It also made use of Game Boy Advance connectivity, in order to replace the Dreamcast's VMU-specific features of the Dreamcast version of the game.
- Big the Cat (from the original Sonic Adventure) cameos in a secret location in nearly every level in the game. Additionally, by pressing A B simultaneously during some cutscenes, Big the Cat will appear and play a secret animation. Curiously, all of these cameos were removed from the Gamecube version.
- Prior to the game's release, Sonic Team went to great lengths to keep Shadow the Hedgehog and Rouge the Bat from being publicly revealed. Only a couple of wide-angle or extreme-close-up images of Shadow were released initially, and Rouge was never mentioned - until toy manufacturer ReSaurus accidentally spilled the beans upon announcing Sonic Adventure 2 action figures. Though ReSaurus went bankrupt before producing these figures, Joyride Studios eventually produced Sonic Adventure 2: Battle action figures.
- In one of the earliest previews on the game, descriptions were given for a number of Sonic Adventure 2 concept drawings. Of them were the first descriptions of the Good and Evil Chao, and Rouge the Bat (then referred to as "Nails the Bat"), but most interesting were descriptions of concept art involving Shadow the Hedgehog ("Dark Sonic" in the preview) - images were described of him bearing a scar across his eye and some pieces of art apparently featured him missing an arm. Other pieces of concept art describe a small troll-like creature with a big nose (possibly Professor Gerald), an angelic woman (most likely Maria), and a monster made out of eyes. These concept images have never been seen by the public.
- The Sonic Adventure 2 demo packaged with Phantasy Star Online for the Sega Dreamcast contained a number of subtle differences from the final release, including a different logo, different road-side billboards in City Escape, more loose controls and game physics, different sound effects, an instrumental-only version of the song "Escape from the City", and even mild swearing in the game's opening cutscene. One of the more noticeable changes comes in the form of Sonic's shoes: as the demo was produced before Sega struck a merchandising deal with shoe manufacturer Soap Shoes, Sonic instead wears his classic red sneakers in the demo.
- In the retail version of Sonic Adventure 2, when Sonic busts out of the Helicopter at the start of the Hero Story, he is still wearing his classic red sneakers. When he straps the piece of metal to his shoes, they appear as Soap Shoes.
- Based on texture/model file names on the Sonic Adventure 2 disc, Shadow the Hedgehog's name might originally have been "Terios". In Japanese, "Terios" translates to several meanings, most notably "Reflection", hinting at his relation to Sonic.
- Sonic Adventure 2 marked the start of the Sonic series officially recognizing both the name "Robotnik" and the name ''Eggman'' as being canon, regardless of region, and the first time a Sonic title uses both names in the story. In Sonic Adventure 2, ''Robotnik'' is established as being Doctor Eggman's family name, whereas the name ''Eggman'' is his more commonly-used nickname or alias.
- A number of texture files in Sonic Adventure 2 are actually high resolution images featuring lengthy amounts of text detailing normally unseen story elements, such as a computer read-out on The Biolizard detailing the creature's life cycle.
- Two unused cutscenes were discovered among Sonic Adventure 2's dialog files, which evidently would have appeared at or near the end of the game's story. The first of these two lost cutscenes is a scene between The President and his Secretary - the President does not believe that heroes exist and has doubt that Sonic and Shadow will be successful in saving the earth, but his secretary urges him not to give up believing in heroes. This scene was restored in the Sonic Adventure 2 anime adaptation featured in the TV series Sonic X, and is actually referenced in 2005's Shadow the Hedgehog. The second lost cutscene is during the credits roll, while Tails and Eggman are reminiscing about Professor Gerald; Eggman turns to walk away, but stops mid-step, declaring he will still conquer the world and he and Tails make a pact that the next time they meet, neither will hold back.
- There are certain lines of English dialogue in Sonic Adventure 2 that do not coincide with the Japanese dialogue. Most notably, in a scene near the end of the game, Shadow declares "Is that what Chaos Control is?" -- the line, if properly translated, would have read "Was that Chaos Control?", or even simply "...Chaos Control?"
- One translation issue is the fact that, during gameplay, some of the characters' voice clips are in fact Japanese exclamations spoken in plain English. (such as Sonic's "TERIA!" and Eggman frequently saying "Yosh!")
- Steve Broadie, who voiced the President (as well as E-102 Gamma in the previous Sonic Adventure), passed away shortly after Sonic Adventure 2 was released.