Sonic Battle

Sonic and his friends find a robot on the beach. Upon establishing a "link" with it, they discover the robot--called a "Gizoid"--can mimic their fighting abilities, learn communication skills, and is powered by Chaos Emeralds. Sonic decides to name him Emerl. The more Emeralds he gets, the more he can grow and learn about the world. Emerl grows and learns from Sonic and his friends, but there are hints that he's more than he appears to be. And Dr. Eggman has plans for him...

Sonic Battle is a 2003 Fighting Game spinoff of the Sonic the Hedgehog series for the Game Boy Advance. It's connected to the Sonic Advance Trilogy trilogy and Sonic Chronicles, through the story of a certain robot and its makers. Unlike most Sonic spinoff games, the focus was more on the story.

The gameplay is simple, yet open to wide variation. There is roaming on small, multi-tiered maps, similar to Power Stone. Each character has a basic combo, advanced directional moves, midair motion and attacks, and supers of the Shot (projectile), Power (direct physical attack) and Set (land-mine type) moves, for both land and air. Each Skill is represented by a Skill Card, which Emerl copies after he's witnessed it in a fight. You have to budget it, however, since each skill costs points, and you have to earn points in battle, and there is a limit to how many points there are.

Game modes include an extensive Story mode, a Challenge Mode, Vs, and several minigames themed for five of the characters.

Tropes used in Sonic Battle include:

Abusive Precursors: The empire that made Emerl. Why? It's spelled out in Sonic Chronicles.
All There in the Manual: A lot of the story of the Sonic games of the 2000s, especially Sonic Adventure 2, were revealed in this game. On the whole, it was second to Sonic Chronicles in this regard.
All Your Powers Combined: This is why Emerl is so special.
Anachronic Order: This game seems to take place after Shadow the Hedgehog due to Shadow's personality, but was released before it.
Animated Adaptation: Sonic X did one to promote the game which was coming out at the time.
Anti-Anti-Christ: Emerl.
Arm Cannon: Tails and Chaos Gamma. For Tails, it materializes when used and disappears after firing a ball of electrical energy.
Artificial Brilliance: On the one hand, the AI will often change its moveset to effectively counter the one you're using, and is fairly good at blocking...
- Artificial Stupidity: ... yet, on the other hand, the AI rarely ever heals itself and, if tag team and friendly fire are on, will often attack its teammates when trying to attack you.
Ass Kicks You: Amy of all people. And Emerl as usual.
Attack! Attack! Attack!: Spammable, powerful moves fall into this category, until the AI wises up and blocks them.
Awesome but Impractical: Knuckles' Ground Shot, the Rockfree Fall, is one of the most powerful shots in the game. However, it is hard to aim and very slow. (The best way to catch someone with it is at close range, as the opponent can be damaged by Knuckles unearthing the boulder before he throws it and knocks them away.)
Awesomeness By Analysis: With the character combos, ultimate skills and ??? skills, Emerl learns how to be better than the other fighters at being themselves.
Beam Spam: For the characters that have exceptionally effective Shot supers.
Beware the Nice Ones: Cream and Emerl. The former will never fight, no matter what the situation. Of course when the need arises, she will step in to help, but will let Cheese do all the fighting.
Bilingual Bonus: The "Ichikoro" gauge is left untranslated. Ichi-koro? One-Hit Kill (hit) K.O.
Bittersweet Ending: Eggman's plans have been derailed yet again, but Emerl was sacrificed in the process. As Sonic notes, however, Emerl's body may be gone, but his spirit still lives on within the Chaos Emeralds. Emerl/G-mel/Gemerl finally gets a happy ending in Sonic Advance 3.
Came Back Wrong: E-102 Gamma returns in this game. However, not only does he sport a new name (Chaos Gamma), he also has no recollection of his past, and is completely subservient to Eggman.
Casino Park: Night Babylon.
Character Customization: Exclusive for Emerl.
Character Development: Emerl. He starts as a nigh-voiceless generic killbot whose only notable detail is his ability to copy other characters' abilities. His interactions with the cast cause him to copy aspects of their personalities as well, and eventually blends them into a complete emergent personality.
The Computer Is a Cheating Bastard: Or at least is far out of your league by design at the very beginning and end of the game.
Continuity Porn: So much stuff is referenced, it isn't funny. They even mentioned Amy's tarot cards, an ability she only had in the Sonic CD instruction manual.
Covers Always Lie: A mild example, but an example nonetheless. You see those moves Sonic and Shadow are performing in the box art above (which are also shown in the game's brief intro)? They don't exist in-game. (You could maybe argue that Shadow is using his Chaos Upper, but the move isn't performed quite like that and his hand glows a purplish color, not green.)
Cut Lex Luthor a Check: Played with; Eggman sells his designs for lesser robots to finance his evil schemes.
Dance Battler: Sonic's melee moves are based on breakdancing.
Decoy Protagonist
Determinator: Even when weakened, Shadow still tries to destroy Emerl.
- Amy is also this when it comes to Emerl and her boxercise training. Rouge even lampshades her persistence in her (Rouge's) story.
Ditto Fighter: The Phi series of robots.
Do Androids Dream?: Emerl most certainly does.
Early Bird Boss: Knuckles is fought with Emerl when he has only a handful of moves and abilities.
Escort Mission: In the first parts of Cream's chapter, she refuses to fight, so Emerl must protect her. Later it's reversed, with Emerl refusing to fight because he doesn't want to make her sad, and she must save him from Eggman's robots.
Fake Longevity: Shadow's challenge at the end of the his chapter, forcing Emerl to track down every other allied fighter at that point and defeat them again before facing Shadow in a rematch.
Financial Abuse: Rouge planned to use Emerl to help her steal jewels.
Fixed-Floor Fighting: There are 3D levels where you can jump from one height to the next, but the stage itself is static.
Flanderization: Amy gets hit with this hard, though she does have moments of her positive Sonic Adventure Series traits.
Foreshadowing: Emerl's quote "Show me your power. Or I sh all not ob ey. I represent all things, and sha ll become Gizoid, the conquerer of all..."
Fragile Speedster: Sonic. Shadow combines it with Glass Cannon.
Freak-Out: Emerl suffers this at the end, forcing Sonic to Shoot the Dog.
Glass Cannon: As noted above, Shadow is both this and Fragile Speedster.
Gotta Catch Them All: The Chaos Emeralds, and their shards.
Green Hill Zone: The Nostalgia Level.
In Medias Res: Sonic's story is the first, but both Shadow's and Rouge's come first chronologically.
Jack of All Stats: Amy and Tails.
Launcher Move: the Upper moves, Heavy moves when the opponent is wall bounced, most Set moves, and some other moves send the opponent into the air for a potential combo.
Let's You and Him Fight: This is how Emerl learns his moves.
Lightning Bruiser: Chaos Gamma in Drive Mode and, eventually, Emerl.
Lost Superweapon: Emerl.
Magnetic Hero: Emerl is a charmer; almost everyone takes a shining to him, leading to a few Enemy Mine fights.
- Which really makes sense, considering Emerl's programed to assimilate personality traits. And naturally, people would want to be around someone more like them.
Mama Bear/Papa Wolf: Threatening Emerl in front of Amy is not the smartest of moves. The other characters can be this in regards to him, especially when Eggman's robots show up. Sonic, in particular, straddles between an overprotective older brother complex and a Papa Wolf.
Mecha-Mooks: The E-121 Phi Robots and the Guard Robots.
Megaton Punch: Knuckles' Ground Power special and Heavy Attack.
Meteor Move: Every character's Pursuit Attack is Type A; they bounce a bit after the first impact with the ground.
Mighty Glacier: Knuckles, Chaos 0, and Chaos Gamma (outside of drive mode).
Mix And Match Android: Emerl's skills and personality are made up of the people he's around. When the first two people he meets are Sonic and Tails, it's commented, "Hmph, I can't tell if he is being polite or rude."
Mood Whiplash: The last chapter.
My Friends and Zoidberg: In the last chapter, as Emerl remembers everyone and the good times he shared with them as he dies, he neglects to mention Rouge.
New Game+: On replay, you receive the chance to earn new skills, and gain more info into the backstory.
No Cutscene Inventory Inertia: Emerl is always the same color in cutscenes.
Nostalgia Level: Green Hill Zone is unlocked upon finishing the game. The Death Egg Ma rk Three is the site of the final boss.
Not So Different: Shadow acknowledges that both he and Emerl are weapons, and spends much of the story trying to destroy the Gizoid. However, Sonic rebuffs this by saying he and Emerl are alike in a different way--both Emerl and Shadow have hearts, and couldn't willingly kill anyone.
Not So Harmless: Of all people, Dr. Eggman. He spends much of the game planning something but not really accomplishing anything, until the last chapter, where he drives Emerl insane with power.
One-Hit Kill: Any Super Attack fully charged through the Ichikoro gauge. Also, the character combos that are exclusive to Emerl can do this.
Only Sane Man: Tails picks this up for once, if only to constantly use his "sad" sprite.
The Power of Love: When Shadow realizes that he needs to relinquish his Chaos Emerald to Emerl in order to complete his evolution, willingly handing over his conduit for his Chaos-based arsenal, Shadow is perfectly fine with such an action. His reply to Rouge?

Shadow: "It's okay. I have Maria in my heart."

Punny Name: Emerl is named after the Chaos Emeralds that power him.
Randomly Drops: Except for the first few battles, new moves are learned randomly. Thus, One Hundred Percent Completion gets all the more frustrating, especially when some moves are at impossibly low rarity.
Running Gag/Overly Long Gag: Chaos Gamma's appearances. To the point of being once or twice per episode except for Emerl's. And even then, you can challenge him whenever you want.
- Also people telling Amy "I don't think that's the case" regarding her delusions about Sonic. By the end of her chapter, even Emerl pitches in, but it's possible he just copied the phrase from everyone else.
Ship Tease: God, there's so much of it for Rouge/Tails it ain't even funny. For example, if you throw the match between Tails and Rouge on the former's storyline Rouge actually kisses him. Tails isn't exactly happy about any of it.
Shoot the Dog: Shadow thinks Emerl should be destroyed for everyone's sake. Also, when Eggman drives Emerl insane, Sonic has to destroy Emerl himself.
Spiritual Successor: To Sonic the Fighters.
Sprite Polygon Mix: Being on the GBA, however, the polygons are limited to stage itself and a few walls.
SNK Boss: Emerl awakened as the Gizoid, who has access to all of the Ultimate Skills.
Stalker with a Crush: Amy, to the point that she considers Emerl to be a child Sonic wanted her to raise.
Taking You with Me: Chaos Gamma's stance has a built-in move called INITIATING RECOVERY MODE. When he is killed, he explodes with this move, and takes significant damage off of the health bars of nearby characters.
The Tease: Rouge.
Technical Pacifist/Martial Pacifist: Cream uses her Chao, Cheese, for melee and super attacks.
Thinking Out Loud: Eggman does this quite a bit. He actually uses this to cause other characters to go along with his plan, though he does it in a rather obvious, near Large Ham like performance.
Victor Gains Loser's Powers: Emerl learns skills from defeating other characters.
Video Game Caring Potential: In full force with Emerl. Which makes the ending even worse.
Voice Grunting
Warrior Therapist: Emerl's emergent personality is primarily the result of the rest of the cast teaching him different ways to respond to adversity. He later returns the favor to Cream.
Wave Motion Gun: The Final Egg Blaster appeared to be this, with enough power to destroy stars.