Super Smash Bros. Ultimate/Classic Mode

Unlike past games, in Super Smash Bros. Ultimate, each character has their own unique Classic Mode route, centered around a theme relating to the character, which may be completed solo or with another player. Upon selecting and confirming a character, you will be taken to a difficulty selection screen, where you can set the initial difficulty from 0.1 to 5.0, and optionally use any available Classic Tickets to increase the rewards earned from finishing the route. As the player progresses, the difficulty will gradually increase, more so for "Nice Play!" bonuses earned from quick or dominant victories, up to a maximum difficulty of 9.9. Players only have one stock to complete each round; should they be KO'd, they can choose to continue either by spending Gold and reducing the difficulty, or using any available Classic Tickets to keep the current difficulty.

Mario
Similarly to Classic Modes from past games, Mario's route has him fight opponents from several series on stages from said series. The concept is also much like Super Mario Odyssey, as Mario is travelling to various "kingdoms".

Donkey Kong
Donkey Kong's route sees Donkey Kong traveling from his home via plane to New Donk City. After defeating Diddy Kong in the first round, he becomes your ally for the rest of the route, a nice nod to the original Donkey Kong Country.

Link
Link's route has him face off with opponents affiliated with darkness, and this and the name of his route are a reference to the main goal of most games in The Legend of Zelda series: to defeat dark entities such as Ganondorf.

Samus
Samus' route features several Metroid references, and sees her facing characters sharing similarities with bosses from her home series.

Dark Samus
Dark Samus's route has her face several protagonist characters, alongside an ally of theirs she has managed to "corrupt".

Yoshi
Yoshi's route sees him fighting several other reptilian adversaries, alongside a few references to Super Mario World and Super Mario World 2: Yoshi's Island.

Kirby
Kirby's route has him face off with several other opponents known for their large appetites (much like the pink puffball himself). In each round except the last, both fighters start with 35% damage and several food items spawn onstage.

Fox
In Fox's route, he fights several other space-traveling characters, culminating in a showdown with his old rival Wolf.

Pikachu
Pikachu's route has it fight several other Pokémon on various Pokémon stages, all ordered by their National Pokédex number. Throughout the route, Poké Balls are the only item that will spawn.

Luigi
Perhaps to face his fears, Luigi faces several creepy or scary characters on his route (or just characters with a "scary" alternate color), finishing with a battle against Dracula himself.

Ness
Ness's route sees a reversed version of his journey in EarthBound, starting in Magicant and ending in Onett, with several references to moments throughout his adventure.

Captain Falcon
Captain Falcon's route is fairly straightforward, seeing him fighting several opponents specializing in close-range combat with few to no projectiles, like the Captain himself.

Jigglypuff
Jigglypuff's route is a big love-letter to the 1P Game of the original Super Smash Bros., as it fights its way through the entire 64 roster, starting with Link and ending with a giant Donkey Kong.

Peach
Peach's route sees her fending off several would-be kidnappers, culminating with her most frequent captor, Bowser.

Daisy
In this route, Daisy squares off against several other princesses in the roster, ending off against her bestie Peach.

Bowser
Bowser's route has him taking down several fighters wearing red, with the final fight being against his age-long nemesis Mario.

Ice Climbers
Fittingly enough for a pair, the Ice Climbers' route sees them facing off with other pairs from several series. Master Hand and Crazy Hand even both appear regardless of difficulty!

Sheik
Much like herself, the enemies of Sheik's route all wear masks or other forms of headwear to hide their identity.

Zelda
Zelda's route has her fighting several antagonistic characters, including four Dark Links and her eternal enemy Ganondorf.

Dr. Mario
Much like the pesky viruses of his home game, the enemies of Dr. Mario's route are all trios using their red, yellow, and blue colors. The trio of Warios at the end could be a reference to the doctor's rivalry with Wario in Dr. Mario 64.

Pichu
As the lightest character in the roster, it's only fitting that Pichu's route has it challenging the other lightweights of the cast.

Falco
In Falco's route, his opponents are all against "dark" forms of main characters, most using alternate colors that reference these characters.

Marth
As a dragonslayer himself, the Hero-King faces several draconic opponents in his route, ending with a duel against a Rathalos.

Lucina
Lucina's route has her battle several other Fire Emblem representatives, in reverse-chronological order of their games of origin.

Young Link
Young Link's route sees him battling the other Legend of Zelda representatives on Zelda stages, and only items and Assist Trophies from the Zelda series will spawn.

Ganondorf
In Ganondorf's route, the Gerudo sorcerer must battle the heroes and protagonists of various series, culminating in his eternal foes Link and Zelda.

Mewtwo
In Mewtwo's route, Mewtwo will be assisted in every round except the first by an enemy from the previous round, all of whom suffered a form of brainwashing in their home series.

Roy
Roy's route has him face off with several other swordfighters in the cast.

Chrom
In Chrom's route, after a bout with Lucina recreating his duel with "Marth", Chrom fights pairs of enemies with his ally alternating between Lucina and Robin, in a nod to the Pair Up mechanic of Fire Emblem Awakening.

Mr. Game & Watch
As the oldest character of the cast, Mr. Game & Watch's route has him fight several other classic fighters in the roster.

Meta Knight
Meta Knight's route has him fight hero characters and their dark counterparts. Every odd round is a free-for-all, while every even round the duo fight as a pair.

Pit
In Pit's route, all the opponents he faces are analogous to enemies he fought in Kid Icarus: Uprising (for example, Dark Samus being a stand-in for Dark Lord Gaol).

Dark Pit
Dark Pit's route is centered around fighting manmade or genetically-enhanced characters, with a battle against his rival Pit for good measure.

Zero Suit Samus
On Zero Suit Samus' route, she mainly fights characters who have a tether grab or recovery, with the exception of Little Mac, who uses his wireframe costume.

Wario
Like Wario himself, all the opponents of his route are characters with brute strength and hard-hitting attacks.

Snake
Snake's route sees him facing several characters with projectile weapons. Only items that are projectile weapons or explosives spawn on this route, as well.

Ike
In a reference to Ike's old rival, the Black Knight, all the opponents of Ike's route use black alternate colors.

Pokemon Trainer
Much like Pikachu, Pokemon Trainer's route has them face several other Pokemon characters. Items are disabled entirely in this route, too.

Diddy Kong
In Diddy Kong's route, he acts as the "sidekick" to several other protagonist characters and helps them defeat their respective nemeses, culminating in teaming up with Donkey Kong to take on their old enemy King K. Rool.

Lucas
In Lucas' route, he fights several other characters with psychic or magical powers.

Sonic
The opponents of Sonic's route are a mix of the fastest characters of the roster and references to the characters and games of the Sonic series.

King Dedede
As the self-proclaimed king of Dream Land, King Dedede battles several other royalty characters in his route.

Olimar
Much like Fox, Olimar fights several other space travelers in his route, including fellow Pikmin protagonist Alph.

Lucario
In Lucario's route, it fights against several other characters with counterattack special moves. Grabs are recommended to circumvent these.

R.O.B.
The opponents of R.O.B.'s route all wear masks or have stoic faces, much like the robot itself.

Toon Link
In a nod to The Legend of Zelda: Tri Force Heroes, Toon Link's route sees him fight opponents alongside two other Toon Links.

Wolf
The opponents of Wolf's route are, much like himself, characters that were absent from Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U (and in the case of Young Link and Pichu, absent from Super Smash Bros. Brawl, as well).

Villager
In Villager's route, their opponents are characters that look like they'd be unsuited to fighting at first glance. Of course, you shouldn't take them for granted because of that.

Mega Man
Mega Man's route draws many parallels to the classic Mega Man games, with many stand-ins for the Robot Masters, the Guts Tank from Mega Man 2, and even Dr. Wily himself.

Wii Fit Trainer
Taking it upon themselves to whip the other fighters into shape, the Wii Fit Trainer face several round or fat characters in their route.

Rosalina & Luma
The opponents of Rosalina & Luma's route are characters from outer space or other planets, with a battle against Bowser as a nod to the Super Mario Galaxy games. Starfy is the only Assist Trophy that can be summoned in this route.

Little Mac
In Little Mac's route, he faces several other close-range martial artists. The only item that spawns in this route is the Sandbag, but no items will appear from hitting it.

Greninja
The opponents of Greninja's route all represent a certain type from the Pokemon series (for example, Charizard and Bowser represent the Fire type).

Palutena
As a goddess herself, Palutena's route has her face characters from series where religion or mythology play a key role.

Pac-Man
The arcade classic Pac-Man faces several characters who appeared on the Nintendo Entertainment System in his route, in chronological order, finishing with a battle against Dracula, the oldest boss character in the game.

Robin
The name of Robin's route is pretty self-explanatory; they face pairs of characters who wield either electricity or fire, culminating in a match against another Robin that is the opposite gender of the player's.

Shulk
In Shulk's route, each of his opponents represent one of his Monado Arts, including Mega Man to represent Monado Enchant, which shared the Monado's ability to damage Mechon armor with Shulk's party.

Bowser Jr.
Bowser Jr.'s route sees him fight several princesses among the cast, occasionally also fighting their love interests (or in Lucina's case, her father).

Duck Hunt
The opponents of Duck Hunt's route are all animals (or in the case of the Mii Fighters, wearing animal costumes).

Ryu
Much like in Street Fighter II, Ryu's route has him face opponents one-on-one in stamina matches, and items are disabled throughout.

Ken
The opponents of Ken's route are all rivals to the main characters of their series, culminating in a match against his own rival Ryu, and a battle against Crazy Hand.

Cloud
As a nod to Cloud suffering from motion sickness (and unfortunately for the man himself), all matches on Cloud's route take place on moving vehicular stages.

Corrin
In Corrin's route, the opponents alternate between black and white alternate colors, representing Corrin's struggle to choose between Nohr and Hoshido in Fire Emblem Fates: Birthright and Conquest.

Bayonetta
Bayonetta's has her fight various winged characters, both as a reference to her battles against angels and specific fights in the Bayonetta series.

Inkling
In Inkling's route, their opponents use alternate colors matching the general color scheme of their stage, as a nod to the Turf Wars of the Splatoon series.

Ridley
Ridley's route sees him attacking other characters who pilot a spaceship, including two skirmishes with his longtime enemy Samus.

Simon
The opponents Simon faces in his route are all monstrous characters, and draw parallels to the monsters fought in the Castlevania series. At the end is a battle against Simon's descendant Richter, followed by the Belmont clan's eternal enemy, Dracula.

Richter
As an Echo Fighter of Simon, Richter's route centers around him fighting the other Echo Fighters of the roster.

King K. Rool
In King K. Rool's route, he squares off against the other heavyweight characters of the cast, including with his old enemy Donkey Kong.

Isabelle
Isabelle's route sees her facing almost every other female character in the roster (excluding Dark Samus and Spiky-Eared Pichu).

Incineroar
Fittingly for the Heel Pokemon, Incineroar's route has a professional wrestling theme, with all fights but the last taking place in various forms of the Boxing Ring stage, against foes who have wrestling-inspired moves.

Piranha Plant
Piranha Plant's opponents in its route are all the newcomers for the base roster of Super Smash Bros. Ultimate. Its final boss Rathalos fits with this theme, being a new boss introduced for Ultimate.

Joker
Joker's route is sort of the opposite of Mewtwo's; on every round except the first and last, Joker will be assisted by an enemy from the previous round with a light alternate color replacing their dark alternate color, serving as a nod to how Joker can recruit various Shadows as Personas in Persona 5.

Hero
Hero's route sees him facing every form of Hero, alongside stand-ins for their allies and various Dragon Quest enemies.

Banjo & Kazooie
Similarly to Ice Climbers, Banjo & Kazooie's route has them face several characters featured as duos, while the stages and music reference several worlds from Banjo-Kazooie.

Terry
Much like The King of Fighters series, Terry's route consists of him facing teams of three in stamina matches, one by one. Terry starts each round with 150 HP, while his opponents start with 100 HP. Also, with the exception of the fourth round, items will not spawn.

Byleth
Byleth's route sees them fight every other Fire Emblem character in a stamina battle. The player always starts with 100 HP.

Min Min
Min Min's route has her fight against various other characters that act as stand-ins for other fighters from ARMS.

Steve
In Steve's route, he fights various characters that act as stand-ins for the hostile mobs of Minecraft. With the exception of the second and sixth rounds, all battles are stamina battles.

Sephiroth
Befitting the final boss of Final Fantasy VII, Sephiroth's route is a boss rush against every boss except Galeem and Dharkon.

Pyra/Mythra
Much like the pair themselves, Pyra and Mythra's route has them face off against pairs of characters that are the same or are similar in some way.