- Michelangelo: Where'd they go?
Leonardo: You mean, where'd we go?
Donatello: Someplace I don't think we're supposed to be.
Teenage Mutant Ninja Turtles 2: Battle Nexus is a 2004 3D Beat 'em Up developed and published by Konami in 2003 for the Nintendo GameCube, Playstation 2, Xbox, and PC. A side-scrolling brawler, also developed by Konami, was made at the same time for the Game Boy Advance, but plays very differently from its console cousins. The game is based on the second season of the Teenage Mutant Ninja Turtles (2003) cartoon.
The vast majority of the season is adapted into a lengthy campaign that consequently follows the story of the second season. After the game re-adapts the final episodes of Season 1, the Turtles are sent into space and become involved in a galactic war between the Triceratons and the Federation, two warmongering alien races. When they finally return home, the Turtles learn some surprising truths about the Shredder and once again contend with the everyday adventures in New York, including a gang war, a trip to the future, further confrontations with the Shredder, and even a journey beyond their own dimension. Aside from the lengthy campaign, the game also features unlockable costumes, a tournament mode that also adapts the Season 2 finale, and a mode set in April O'Neil's antique shop Second Time Around, in which the player can unlock pieces of concept art, pieces of lore from the show, and even the original arcade game ported for a new generation of fans.
The four Turtles Leonardo, Donatello, Raphael, and Michelangelo are the default playable characters, and a major innovation of the game is the expansion to four total potential players at once compared to the last game's two. Each Turtle has their own unique abilities and special attacks which the expanded group of players can use to coordinate with against enemies and the game's playable areas. This game also features a secondary roster of unlockable characters - Casey Jones, Master Splinter, Karai, and Canon Foreigner Slashuur, a character created exclusively for the game.
The game was followed in 2005 by Teenage Mutant Ninja Turtles 3: Mutant Nightmare, which adapts the third season of the show, and Teenage Mutant Ninja Turtles Mutant Melee, a fighting game.
- Absurdly Sharp Blade: Leonardo's gimmick is the ability to slice through certain obstacles with his swords, including things like metal fences, bamboo stalks, and the occasional concrete pillar. Slashuur and Karai can do the same (although with Slashuur it's at least somewhat more believable).
- Adaptation-Induced Plot Hole: The game adds in the Turtles visiting an original world, Planet Zero, before teleporting to D'Hoonib and uses original cutscenes made for the game to depict the scenes there. However, when the Turtles arrive on D'Hoonib, they react as if they have just come from the TCRI building, wondering where the Utroms are, since the game is now using scenes from the actual show.
- Adapted Out:
- Battle Nexus notably features adaptations of nearly every single episode of Season 2, making it easy to list the few episodes that don't get adapted: "Reflections", "The Return of Nano", "Junklantis", "The Golden Puck", "April's Artifact", and "Return of the Justice Force". This means that the characters of Nano, Garbageman, and the Justice Force fail to put in an appearance.
- Gennosuke is also absent from Battle Nexus when Usagi does appear.
- Adaptation Distillation: The chapter adapting the events of "Return to the Underground" open up after the player completes the first chapter and is easier than the chapter adapting "The Search for Splinter", suggesting the game is encouraging the player to complete that chapter first. "Return to the Underground" is an episode that took place well into the second season, whereas "The Search for Splinter" is the season 1 finale.
- Arm Cannon: In the first mission of Battle Nexus, Donatello gets an arm-mounted laser gun that replaces his shuriken attacks with a Slow Laser that bounces off walls.
- Ascended Extra: The Ninja Rats are fought twice here and can talk.
- Boss Bonanza: The final stage of the campaign has a boss fight for just about every level. You have to go through the four Foot Elite, Hun, Karai, and a two-part Final Boss with the Shredder.
- Boss Rush: The eponymous tournament, only accessible after completing the main story, is basically a long series of boss fights against previously-encountered opponents, ending with a fight against Miyamoto Usagi and another against Drako.
- Bottomless Pits: All over the place, often around platforming sections. Falling in won't instantly kill you, though, instead sending you back to the nearest solid ground after making you take a chunk of damage (although there's a cheat code to make them kill you). The ability to pick up and throw enemies in this game means they can also be easily weaponized.
- Breakable Power-Up: The Doppelganger ability present in this game and Mutant Nightmare gives an extra health bar and can be carried over between levels. However, once your extra health bar is depleted, the Doppelganger is gone and you'll have to get another one to use it again.
- Canon Foreigner: While most characters are taken from the TV series, the games introduces the scythe-wielding Noble Demon Slashuur, who is fought several times as a boss and serves as a playable Secret Character.
- Charged Attack: Once unlocked, holding down the Strong Attack button will cause a turtle to charge up a super move. The more the move is charged, the stronger it becomes, with three possible levels of power.
- Classic Cheat Code: Though present in all three games, they really only started getting interesting in this one. The second and third games will randomly show you a code that you can enter in the settings menu (but only once and will urge you to write them down), but not what the code does... and cheat codes in this game range from making you invincible or replacing all healing items with pizza (which is a full heal), to making you die in one hit.
- Climax Boss: An interesting example in the beginning of the game. The first levels adapt "Return to New York" and have Hun as the boss, with the Shredder only being fought in a cutscene afterwards. The Shredder himself serves as the actual Final Boss of the game.
- Defeat Equals Explosion: Robotic enemies tend to explode on death, but unlike the first game, the explosion actually does damage here.
- Degraded Boss:
- Razorfist and King Nail were fought in the penultimate stage of the first game as powerful solo bosses. But in Battle Nexus they're fought in the first stage after the tutorial stages and are considerably easier.
- Inverted with Hun, as he's the first boss of Battle Nexus but you fight him again in the last stage as the 3rd last boss, this time sporting a second phase and harder attacks.
- Dual Boss:
- Razorfist fights alongside an unnamed spider mutant.
- The Foot Fight tournament sees you face off with two Elite Guardsmen, which can turn into four once they use their shadow warrior attack.
- Escort Mission: One mission where you have to escort the Fugitoid through the streets of D'Hoonnib, with a time limit attached. Furthermore, the Fugitoid doesn't move on his own, meaning you have to pick him up and carry him (rendering the player carrying him entirely defenseless while slowing them to a crawl) through an area infested with Federation soldiers out for both your blood and his, and every time you have to put him down or throw him aside to fight enemies, the Fugitoid takes damage. Have fun.
- Exploding Barrels: Barrels in this game explode when hit with any attack; however, this game lets you pick them up and throw them. They also come in three color-coded flavors: red barrels create the expected fiery explosion, blue barrels create an icy explosion that causes Harmless Freezing, and green barrels spread knockout gas.
- Glass Smack and Slide: This can be done to humanoid enemies, either with attack knockback or by picking them up and throwing them at a wall. The Turtles can also be subjected to this.
- High-Altitude Battle: The second battle against Slashuur takes place on a glowing platform suspended in midair. Incidentally, this level is also titled 'Air' like the last game's fight with the Turtlebot.
- Legacy Boss Battle:
- Hun is fought once again, with similar attacks each time.
- Razorfist and King Nail, after being fought in the first game, both return as mini-bosses.
- Mirror Boss: In addition to using melee attack combos similar to the ones players have access to, the Foot Mech Splinter can also use all four turtles' super moves and has EyeBeams to emulate Donatello's laser gun.
- No Fair Cheating: While the game otherwise doesn't prevent you from using cheat codes, Battle Nexus disables their effects in the tournament modes.
- Nostalgia Level: In "The Cavern" level, while taking an elevator to a lower level, you can see the pathway from levels in the "Notes from the Underground" chapter from the first game off in the distance.
- Percussive Shutdown: Donatello's unique gimmick is the ability to access consoles to shut them down. Splinter, who occupies the same character slot as Donatello, can also do this by hitting the console with his walking stick.
- Promoted to Playable: Splinter, Karai, and Casey Jones become playable characters, although they must first be unlocked.
- Recurring Boss: Slashuur and Hun are fought twice each in Battle Nexus, and both can optionally be fought a third time in Tournament Mode.
- Ring-Out Boss: The Feudal Shredder is fought atop a cliff. Smacking him off it defeats him instantly, although you can also beat him up the old-fashioned way.
- Schmuck Bait: The randomly-given passwords in this game and Mutant Nightmare. The game periodically shows you a cheat code you can enter, but it does not show what that password does, and not all of them are positive. Sure, the game could give you an invincibility cheat code or unlimited shuriken, or it could take away healing items entirely or make you die in one hit to everything.
- Shared Life-Meter: You can cycle between turtles at will, but no matter who takes damage, it all comes out of that single health bar. If you're playing multiplayer, everyone shares that health bar. On the enemies' side, the Ninja Rats also have this mechanic.
- Suddenly Speaking: The Ninja Rats talk here.
- Teleport Spam: The Ultimate Ninja teleports at every opportunity after being hit. You'll be seeing him doing it a lot.
- True Final Boss: Drako as he is the final opponent of the post-game Battle Nexus tournament.
- Turns Red:
- Hun upon hitting half life literally turns red, and gains a massive increase in speed.
- Most of the bosses will become more powerful at low health, usually indicated by some sort of Battle Aura. This can give them new attacks, improve their existing attacks, make them Immune to Flinching, or any combination of the above.
- Unexpected Gameplay Change: The game has stages where the turtles ride hoverboards to collect coins instead of the usual beat-em-up gameplay. Two stages have them piloting spaceships instead.
- Video Game Dashing: Leo's dash in this game actually deals damage since he puts his sword in front of him while dashing.
- Wake-Up Call Boss: If you haven't figured out the combat system by the time you fight Slashuur, he'll make sure you know it well by the time you finally beat him. Otherwise, have fun getting torn apart by his powerful, life-draining attacks.
- Wall Jump: The turtles can do this and doing so is required for navigating certain platforming sections.
- The War Sequence: The level adapting "City at War" depicts dozens of enemies from the three factions - the Foot, the Purple Dragons, and the Mafia - at war with each other in the streets, and the player must defeat a set amount of enemies from each faction to clear the stage.
- Warm-Up Boss: Hun, who fights you with mostly basic melee attacks and a Ground Punch that drops chunks of the ceiling, none of which are particularly threatening, and he has no other gimmicks other than becoming Immune to Flinching if you hit him enough in succession. When you fight him the second time late in the campaign, he stops holding back.
- Wolfpack Boss: The Ninja Rats. You fight all 4 of them simultaneously, but they have a Shared Life-Meter; once it runs out, all four of them fall over.
- Written Sound Effect: Explosions, stun effects, and attack hits are all labelled with one of these, but they are down for this game.
