Adventure Mode: The Subspace Emissary

Adventure Mode: The Subspace Emissary, otherwise known as simply The Subspace Emissary or Subspace Emissary, is an adventure mode in Super Smash Bros. Brawl. Unlike Super Smash Bros. Melee's Adventure mode, The Subspace Emissary has a proper storyline and unique levels, and it takes place in the World of Trophies.

Gameplay
The mode features 2.5D platforming gameplay. When playing The Subspace Emissary, the player can choose from five difficulties: Easy, Medium, Hard, Very Hard, and Intense.

The Subspace Emissary uses a team system. Two players can play in the Subspace Emissary at one time, with second player being an optional supporting character. Due to the camera following the main character, if the second character cannot follow the scroll and becomes off-screen, they are automatically warped. If Player 1 is defeated, and Player 2 is not, the game will still be over. Also, by pressing the Start or Plus Button, Player 2 can always warp to wherever Player 1 is. This, however, does not work during boss battles in the Emissary. The main screen shows where to go next, and the character selection screen allows the player to choose their team. In single player, teams are still available. However, the second character is akin to an extra life, and if the main character is defeated, the player takes control of the second character, until it, too, is defeated.

The player can use Sticker power-ups for the mode. The stickers are arranging on the character's Trophy Stand and give bonuses on Launch Power, Launch Resistance, and powers and resistances to several attacks like Arm, Weapon, Slash, Electric and Flame. The effects vary from sticker to sticker. When the player loses all of their lives, they can be asked to continue but stickers and enemy turned trophies will be cut in half, if they decide to quit, they will get a Game Over and lose half of their stickers but they may keep the trophies. The player has a choice to save game progress after completing each level.

All unlockable characters can be unlocked by playing The Subspace Emissary; the player can only unlock three of them after clearing The Subspace Emissary and then battling each fighter in a fight.

Plot
The Subspace Emissary is the adventure and story mode of Super Smash Bros. Brawl, taking place in the World of Trophies, where being defeated in battle turns a character into a trophy. The story begins with the Subspace Army, riding the Halberd, interrupting a fight between Mario and Kirby, while Peach and Zelda watch from the stands. The mysterious Ancient Minister deploys a Subspace Bomb controlled by two R.O.B.s, and while Mario tries to intercept it, he is knocked away by Petey Piranha, who has captured both princesses. Kirby defeats Petey and rescues one princess, while Wario steals the other, and after they all leave, the bomb detonates and the arena is consumed by Subspace.

Fox attempts to fight the Halberd in his Arwing but is struck down by the larger vessel and crashes in a jungle, where he joins forces with Diddy, who has been separated from Donkey Kong earlier by Bowser. They are joined by Falco and eventually Captain Falcon and Olimar, and together they save Donkey Kong from the Subspace Army, at which point Fox and Falco leave to resume their battle with the Halberd, now assisted by their carrier ship, the Great Fox.

Elsewhere, King Dedede captures Luigi and uses him as bait for Wario, stealing his transport and all his trophies (including Luigi himself) when he is distracted. Wario is then defeated by Lucas and Pokémon Trainer in retaliation for capturing Ness earlier. After Pokémon Trainer catches Charizard, he and Lucas meet up with Marth, Meta Knight and Ike, who has already joined forces against the Subspace Army. They witness the Halberd battling the Great Fox, prompting Meta Knight to scale the cliffs in an attempt to reclaim his ship. On the way up, he is joined by the Ice Climbers and on the summit he teams with Lucario after an initial duel. The Ice Climbers fall when the Halberd smashes the tethered Great Fox against the mountain, but Meta Knight and Lucario take the opportunity to board the ship.

Meanwhile, Pit finds and revives Mario, while Link and Yoshi join forces against the Subspace Army. When Kirby wanders off, the second princess is captured by Bowser, who makes a clone of her. If the clone is of Peach, it attacks and is defeated by Link, which is witnessed by Mario, who retaliates; if the clone is of Zelda, it is defeated by Mario and Link attacks him instead. Either way, the combatants realize the misunderstanding when Dedede drives by with the other princess statue, spurring them to team up against their common enemy. They tail him back to his castle but are unable to stop Bowser from crashing in and taking the princess, leaving behind a badge that King Dedede had put on his three stolen statues. The heroes then meet up with the Ice Climbers, Lucas, Pokémon Trainer, Marth, and Ike.

While all that is happening, Zero Suit Samus infiltrates the Subspace Army's base on the floating Isle of the Ancients, rescues Pikachu, recovers her Power Suit and battles Ridley. She and Pikachu make their way to the Subspace Bomb depot at the same time as Diddy, Donkey Kong, Captain Falcon, and Olimar, who has ridden an enemy barge to the island. They are confronted by the Ancient Minister, but after sacrificing so many R.O.B.s to detonate numerous Subspace Bombs by that point, he is unwilling to fight the Smashers. His commander Ganondorf then takes control of the robots and they shoot the Ancient Minister, burning away his clothes to reveal that he is also an R.O.B. The controlled robots all activate bombs, and unable to stop them, the heroes flee on the Falcon Flyer.

Back on the Halberd, Meta Knight and Lucario team up with Snake, free the captured princesses and kick a crew of Mr. Game & Watch clones out of the cockpit. Peach and Zelda (in her Sheik disguise) make their way onto the deck as Fox and Falco attack in their Arwings, and when the exchange of shots nearly hurts Peach, Sheik retaliates and forces Fox to eject from his Arwing. Peach diffuses the tense situation by offering both Sheik and Fox tea, however, and along with Snake, Lucario and Falco, the trio defeat the Duon robot that forms from the Mr. Game & Watch clones, freeing the real Mr. Game & Watch. Meta Knight then takes the helm and flies the Halberd to shore at the same time as the Falcon Flyer lands, uniting the three groups of combatants.

Ganondorf and Bowser use the massive sphere of Subspace that had engulfed the Isle of the Ancients to bring a giant gunship into the World of Trophies and use it to fire larger Subspace blasts. The Halberd attacks and is destroyed, but this was cover to allow a group of the Smashers' smaller ships to get in close and infiltrate Subspace. Kirby also destroys the gunship with the Dragoon. The villains retreat, but Ganondorf betrays Bowser, transforming him into a trophy as he alone visits Master Hand, only to find he has been under the control of Tabuu all along. Tabuu immediately defeats Master Hand and transforms Ganondorf and all the protagonists into trophies.

King Dedede's badges, however, revive Ness, Luigi, and Kirby, who has eaten the dropped one, and they rescue everyone else, both allies and former enemies. Banded together against Tabuu, the group head through The Great Maze, defeating all the bosses and dark versions of themselves. Once they reach Tabuu, Sonic arrives and destroys his wings, preventing him from transforming the group back into trophies again, and together, the Smashers defeat Tabuu and restore the World of Trophies.