Unlock Characters

Boogie - Find her at Kibogaoka Hill
Garam - Finish all Garams challenges
Beat - Defeat him on street race
Combo - Finish Combos Challenges
Rhyth - Find her at the top of the Poison Jam warehouse in Rokkaku-dai Heights. Then find her 2 more times in the game
Soda - go to highway Zero and find a guy dancing is the blue dot on the map talk mto him race him and win
Jazz - after death ball go back to the stadium and challange jazz to a race.
Cube - after tagging all of the Monsters in the under ground sewer facility she appears after you beat the game then go talk to her and race her

Unlock Zero Beat

Clear Shibuya Terminal and clear all the challenges and get all the graffiti souls and finish all the test runs on that level and you will get Zero Beat.

Unlock Clutch

A little while after yoyo gets kidnapped clutch comes and takes your graffiti souls. First go to Rokkaku Dai Heights then go to the middle of Pharoah Park and talk to him. You dont have to race him or beat him in anything, he just joins you.

Poison Jam

Beat the game. Then get all the graffiti souls in the sewer area. Talk to Roboy and select "test run."Earn a "jet" ranking in all the categories selectable for the area.Poison Jam will be selectable

Roboy

Beat the game. Earn all graffiti souls in the Chuo Street area. Talk to Roboy and select "test run." Earn a "jet" ranking in the selectable test run categories for that area. Roboy will become playable.

Love Shockers

Beat the game. Then earn all graffiti souls in the Hikage street area. Talk to roboy and ask for a test run.Earn a "jet" ranking in the categories of test run for that area. The Love Shockers will be playable.

Noise Tanks

Beat the game. Then earn all graffiti souls at highway zero. Talk to Roboy and ask for a test run for that area. Earn a "Jet" ranking in the categories that are selectable for that area. Noise Tanks will be playable

NT-3000

Beat the game. Then collect all graffiti souls at Sky Dinosaurian Square. Talk to Roboy and choose to do a test run on that area in the catagories that the area is selectable. You must earn a "jet" ranking in each. Afterwords "Nt-300" will be playable. Nt-3000 is the robotic clone of yo-yo.

Doom Riders

Beat the game. Then, collect all graffiti souls in the Dogenzaka hill area. Talk to Roboy to run a test run for the three catogories that are available. You must earn a "jet" ranking in all catagories. The Doom Riders, (the guys you played in death ball) will be unlocked.

How to Unlock Test Runs

On each level there is a secret tape. When you get the tape press start and read the GG Notebook. You will have about 5 challenges to complete. once you complete all of the challenges and get all the graffiti souls you have a test run on that level. Oh and one more thing the graffiti souls are those white heads like the one on the cover of the game or the press start screen.

Gouji

Beat the game and get all graffiti souls in the bottom point of the sewer and all of the souls in rokkakau dai heights. Talk to roboy and ask for a test run. Earn a "Jet" ranking in all the catogories available for each area. Rokkakau Gouji will become playable.

Starting game hint

Use the GGs leader Corn in the start of the start of the game until you get to Beat in Doganza Hill. Follow him a couple times then hell challenge you to a race.Use Gum to race. Hell join you when you win. Then use Beat or Corn until you get some one else besides a guy with a stereo named Combo

Unlock DJ ProfesserK

While selecting a character, pick Piahna, then press A,Y,X,X,B,and Y while she is dancing

Unlock Immortals

Complete all the challenges and test runs on The Skyscraper District and Pharoah Park to unlock the Immortals

Unlock Regular Gouji

Complete all the challenges and test runs on Rokkaku-Dai-Heights to unlock the Gouji as a regular person

Unlock A. Ku. Mu

To unlock A. Ku. Mu you must beat The fortified residential zone in test run and get all jet on the three runs(A.Ku.Mu is the final boss of the game that Gouji Rokkaku transforms into).