Unlockables

Belt Ranks

Listed below from worse to best are the coloured belts and where they rank against each other.
White
Yellow
Blue
Green
Purple
Red
Brown
Black

Extra Minions

Reaching Rank 80 with a certain amount of characters will unlock new minions.

Curtis the Panda (Carnival Island) - Reach Rank 80 with 2 characters
Dr. Nefarious (Ratchet and Clank) - Reach Rank 80 with 3 characters

Minions and Costumes

There are unlockable minions and costumes for every character which can be acquired by reaching a certain rank with that character.

Alternate Costume - Reach Rank 10 with any character
Minions - Reach Rank 8 with any character

Trophies

Trophy: Fearless DLC

There is 1 Silver Trophy.

The Heavenly Goddess (Silver) - Perform a Level 3 Super with Nariko on 'Fearless'

Platinum

All-Star Legend - You've Only Done Everything - You have successfully earned all other trophies in the game. Congratulations!

Gold

Three for One - Earn a Triple Kill with a Level 1 Super Attack

Silver

Triple Kill! - Earn a Triple Kill in a match-made online game
Team Sweeper - Earn a Double Kill in a 2v2 match-made online game
3x OVERTIME!! - Enter 3x AP Overtime!
Champion - Win a Versus Match against a team of three AI opponents
Combo Virtuoso - Land a 70+ AP Combo in Practice Mode
Victorious! - Win a match-made online game
Two for One - Earn a Double Kill with a Level 1 Super Attack
This is Living - Win a match-made online game without dying

Bronze

Trial Combatant - Complete a Combat Trial
The Legend - Complete Arcade Mode on Legend
Fundamentals - Complete the Basic Tutorial
Character Mastery - Complete a Combo Tutorial
Showing Off - Show off your Minion during a game
We have Overtime! - Working Weekends? - Enter Overtime!
Combo King - Land a 50+ AP Combo in Practice Mode
Ultimate Power - Perform a Level 3 Super Attack
Friendly Competition - Complete a Versus Match against an online player
Tournament Fighter - Complete an online Ranked Match
First Blood - Earn a Kill in a match-made online game
The God of War - Complete Arcade Mode with Kratos
I Gotta Believe! - Complete Arcade Mode with PaRappa
Cake, please! - Complete Arcade Mode with Fat Princess
Oh Boys and Girls - Complete Arcade Mode with Sweet Tooth
Helghast Commander - Complete Arcade Mode with Radec
Thievius Raccoonus - Complete Arcade Mode with Sly Cooper
Treasure Hunter - Complete Arcade Mode with Nathan Drake
Greatest Conduit - Complete Arcade Mode with Cole
Friend of the People - Complete Arcade Mode with Toro
Monkey Catcher - Complete Arcade Mode with Spike
Intergalactic Heroes - Complete Arcade Mode with Ratchet
Eco Master - Complete Arcade Mode with Jak
Let's Make a Scene - Complete Arcade Mode with Sackboy
Revengeance - Complete Arcade Mode with Raiden
The Iron Fist - Complete Arcade Mode with Heihachi
Mr. Bubbles - Complete Arcade Mode with Big Daddy
Demon Hunter - Complete Arcade Mode with Dante
Demon of Empire City - Complete Arcade Mode with Evil Cole
Heavenly Warrior - Complete Arcade Mode with Nariko
Hero of Gallowmere - Complete Arcade Mode with Sir Daniel
I Chose The Impossible - Perform a Level 3 Super with Big Daddy on 'Columbia'
Master of the Ray Sphere - Perform a Level 3 Super with Cole or Evil Cole on 'Alden's Tower'
Interpol HQ Break-In - Perform a Level 3 Super with Sly Cooper on 'Paris'
Kerwan’s Capital City - Perform a Level 3 Super with Ratchet on 'Metropolis'
Ally of Larry Da Vinci - Perform a Level 3 Super with Sackboy on 'Dreamscape'
Calypso’s Wishes - Perform a Level 3 Super with Sweet Tooth on 'Black Rock Stadium'
The Doctor Is In... - Perform a Level 3 Super with Ratchet on 'San Francisco'
Student Becomes the Master - Perform a Level 3 Super with PaRappa on 'Dojo'
REX versus RAY - Perform a Level 3 Super with Raiden on 'Franzea'
The Peak Point Helmet Blues - Perform a Level 3 Super with Spike on 'Time Station'
Samos’ Sacred Site - Perform a Level 3 Super with Jak on 'Sandover Village'
Sic Parvis Magna - Perform a Level 3 Super with Nathan Drake on 'Stowaways'
Autarch of Helghan - Perform a Level 3 Super with Radec on 'Invasion'
Palace of the Underworld - Perform a Level 3 Super with Kratos on 'Hades'