Note: This game is also known as - Dairantou Smash Brothers X

There are 6 secret assist trophies in total. Below are the methods for unlocking them.

Advance Wars Assist Trophy Play 300 brawls.

Barbara Assist Trophy Unlock 25 or more CDs.

Gray Fox Assist Trophy Unlock Snake.

Isaac Assist Trophy Play 200 brawls.

Ray MK III Assist Trophy Play 100 brawls.

Shadow the Hedgehog Assist Trophy Unlock Sonic the Hedgehog.

Unlock More Rules - More Rules Is Located On the Rules Screen At The Bottom

More Rules Get 200 KOs In Standard Brawl

Unlock Virtual Console Trials

Donkey Kong Exceed 10 hours of play time

F-zero Beat SSE having used captain Falcon

Legend of Zelda: Ocarina of Time Use Toon Link over 10 times

Super Mario USA Win in VS mode with Peach over 5 times
Super Mario World Play yoshi's Island (melee) over 3 times

Unlockable Characters

Captain Falcon 70 Brawl Matches OR Have him join in SSE OR Beat Classic in 12 minutes or less then defeat him in the following match

Falco 50 Brawl Matches OR Have him join in SSE OR Complete 100-man brawl

Ganondorf 200 Brawl Matches OR Collect Zelda and Link trophies in SSE to have him join you OR Clear Classic on Hard with Link or Zelda

Jigglypuff 350 Brawl Matches OR Fight her in Swamp stage in SSE after completing it OR complete SSE then Events 1-20

Lucario 100 Brawl Matches OR Have him join in SSE OR Complete all 5 Target Tests with a character
Luigi 22 Brawl Matches OR Have him join in SSE OR Complete Classic without continuing

Marth 10 Brawl Matches OR Have him join in SSE OR Finish Classic on any difficulty
Mr. Game & Watch 250 Brawl Matches OR Have him join in SSE OR Clear Target Tests on any level with 30+ characters

Ness 5 Brawl Matches OR Have him join in SSE OR Reflect ten projectiles

R.O.B. (Robot) 160 Brawl Matches OR Have him join in SSE OR Get 250 different Trophies

Snake 130 Brawl Matches OR Have him join in SSE OR Play 15 matches on Shadow Moses Island
Sonic 300 Brawl Matches OR Have him join in SSE OR Beat Classic Mode with 10 characters

Toon Link 400 Brawl Matches OR Fight him in Forest stage in SSE after completing it OR After beating SSE, finish the Classic mode

Wolf 450 Brawl Matches OR Fight him in Ruins stage in SSE after completing it OR Complete Boss Mode with Fox or Falco

Unlockable Events

Co-op Event 21 Complete all 20 Co-op Events
Co-op Events 14-20 Complete 10 Co-Op Events and unlock all hidden characters
Co-op Events 9-13 Complete the Subspace stage in Adventure Mode

Event 41 Complete all 40 evnts
Events 11-20 Complete 7 events
Events 21-28 Complete the Subspace stage in Adventure Mode
Events 29-40 Unlock all hidden characters

Unlockable Modes

All-Star Mode Unlock all the hidden characters
Boss Battle Mode Complete the Subspace Emissary

Unlockable Music

02 (Zero Two) Boss Theme (Kirby 64) Have a total of 5000 coins collected in vs. coin matches
100-Man Melee 1 Clear 100-Man Brawl under 4 minutes
3D Hot Rally Title Clear Target Level 5 With Anyone
Ai no Uta (French Version) Hit 37,500ft. combnd with all fighters' Home-Run Contest records.

Bob-Omb Battlefield (Super Mario 64) Have a total of 50 hours of vs. gameplay

Clu Clu Land Hit 1,200 feet or more in Home-Run Contest with any character

Dragon Roost Island Unlock Toon Link
Dream Chaser Play 10 vs. matches on Port Town

Echoes (Metroid Prime 2) Brawl on the Frigate Orpheon stage 10 times
Ending (Metroid) Play 10 vs. matches on Norfair
Excite Truck Complete Target Test Lv.2 under 19 seconds with any character

Fire Field Complete Event #24
Frozen Hillside Play on the Halberd stage 10 times in VS mode

Goruda Play 10 vs. matches on Halberd
Great Temple Complete Event #33 on Difficult

Ice Climbers (Melee) Clear Classic Mode on Easy with any character
Icicle Mountain (Melee) Clear Classic on Normal Difficulty with any character
Ike's Theme Find Ike in the Subspace Emissary

King Dedede's Theme Complete Event #15
Kuru Kuru Land Get a distance of 400m in Home-Run Contest with one character

Legendary Air Rider Machine Complete Event #13
Love Song (commercial version) Get a combined distance of 12500m in Home-Run Contest

Mach Rider (melee version) Defeat 50 alloys in Endless Multi-Man Brawl
Menu 2 Unlock All 35 Characters
Metroid Prime 2: Multi-Play Play 10 vs. matches on Frigate Orpheon
Molgera Battle Unlock Toon Link
Mountain and Forest Complete Event #18 on Difficult

Peach Castle (Melee) Unlock all Melee stages
Pokémon Center Collect 200 stickers
Powerhungry Fool Play 10 vs. matches on Castle Siege

Road to Tokiwa Complete Event #8

Snake Eater Play 15 vs. matches on Shadow Moses Island
Song of Storms Complete Event #37
Staff Credits Music Clear Classic Mode on Difficult
Star Wolf (Star Fox: Assault) Complete Event #38 on Difficult

Taru Taru Highlands Clear All-Star Mode on Easy
The Great Sea Unlock Toon Link
Title from 3D Hot Rally Clear Target Smash Level 5

Underwater BGM (Super Mario Bros) Play 10 vs. matches on Mushroomy Kingdom

Unlockable Stage Builder Parts

Edit Parts A Play 10 vs. matches on Stage Builder Stages
Edit Parts B Create 5 Stages in Stage Builder
Edit Parts C Create 15 Stages in Stage Builder

Unlockable Stages

75m Brawl as Donkey Kong 20 times

Big Blue (Melee) Brawl as Captain Falcon 10 times

Flat Zone 2 Unlock Mr. Game & Watch

Great Sea Unlock Toon Link
Green Greens Fight as Kirby in VS mode 20 times
Green Hill Zone Unlock Sonic

Hanenbow Complete Event #28

Jungle Japes Play on any Melee stage 10 times in VS Mode

Luigi's Mansion Use Luigi in brawl 3 times

Mario Bros Beat Challenge #19

Pokémon Stadium Play on Pokémon Stadium 2 10 times in VS Mode
Spear Pillar Clear stage #25 in Event Mode

Unlockable Stickers - There are certain stickers in the game you cannot randomly collect off the ground, in which you must meet specific requirements to achieve these stickers.

Boo [Mario Tennis] Hit over 900 ft. in the Home-Run Contest
Liquid Snake [Metal Gear Solid: The Twin Snakes] Defeat 10 Alloys in Cruel Brawl
Phyllis [Animal Crossing: Wild World] Clear All-Star mode on Normal difficulty with any character
Running Chibi-Robo [Chibi-Robo] Clear Classic mode on Easy difficulty with any character
Ryuta Ippongi [Duendan 2] Clear 100-Man Brawl in under 3 minutes, 30 seconds

Unlockable Target Tests - By clearing various difficulties of Classic, you can unlock different levels of Target Test as outlined below. Note that if you unlock a higher difficulty level before an lower one, you will unlock all the ones before it e.g. If you clear Classic mode once on Intense, you will unlock all the target tests.

Level 2 (Medium) Beat Target Test in Classic Mode twice on Easy or once on Medium

Level 3 (Hard) Beat Target Test in Classic Mode twice on Medium or once on Hard

Level 4 (Very Hard) Beat Target Test in Classic Mode twice on Hard or once on Very Hard

Level 5 (Intense) Beat Target Test in Classic Mode twice on Very Hard or once on Intense