You must tag all tag spots, complete all Street Challenges, and get all the Graffiti Souls to unlock the Test Run in each specific area. In the Test Runs, you can unlock more characters.
Hidden Character A.ku.mu.
Earn a "Jet" ranking at Fortified Residential Zone.
Hidden Character Beat
Defeat him in a street race.
Hidden Character Boogie
She can be found at Kibogaoka Hill.
Hidden Character Clutch
Follow DJ Professor K's instructions.
Hidden Character Combo
Successfully complete his challenges.
Hidden Character Cube
Defeat the Noise Tanks At Sky-Dinosaurian Square, then go to the bottom of the Sewage Facility and defeat Cube in the City Rush.
Hidden Character Doom Riders
Earn a "Jet" ranking at Dogenzaka Hill.
Hidden Character Garam
Complete his challenges.
Hidden Character Goji Rokkaku
Earn a "Jet" ranking at Rokkaku-Dai Heights.
Hidden Character Immortals
Earn a "Jet" ranking in Skyscraper District and Pharaoh Park.
Hidden Character Jazz
Go to the future site of Rokkaku Expo Stadium. Defeat Jazz at City Rush
Hidden Character Love Shockers
Earn a "Jet" ranking at Hikage Street.
Hidden Character Noise Tanks
Earn a "Jet" ranking at Highway Zero.
Hidden Character NT-3000
Earn a "Jet" ranking at Sky-Dinosaurium Square.
Hidden Character Poison Jam
Earn a "Jet" rank in a test run at the Tokyo Underground Sewage Facility and at the bottom of Sewage Facility.
Hidden Character Potts
Earn a "Jet" rank at Kibogaoka Hill.
Hidden Character Rapid 99
Earn a "Jet" rank at 99th Street.
Hidden Character Rhyth
Go to the top of the Poison Jam warehouse in Rokkaku-dai Heights to find her the first time. Follow and find her two more times in the game.
Hidden Character RoBoy
Unlock A.ku.mu., then earn a "Jet" rank at Chou Street.
Hidden Character Soda
Defeat Soda in City Rush at Highway Zero.
Hidden Character Zero Beat
Earn a "Jet" rank in a test run at Shibuya Terminal.
Beating Poison Jam At Underground Sewage Facility
When you get to the part in the Tokyo Underground Sewage Facility where you have to tag Poison Jam( Tagger's Tag), look in the places where the blue mist come out. Two of them will be there, and the last will be in the next room after that, this room however does not shoot blue mist. Don't worry about time limits, once they get there, only on rare occasions will they even try to go back up, and even if they do, they come back in a few minutes. Another good thing to do is to get up right behind them and spray, and when they turn, turn with them. Just keep on their tales until their damage meter is full and they stop, hold their hands utheir not going to bother you.
Skateboarding hobo
Go to Dogenzaka Hill. Go all the way down to the place where the statue is located, or is supposed to be. Then, skate down the object that resembles a roof. When you fall off the big roof, turn around and look at the drop that you just fell off from. If done correctly, you can look to the right and see a man wearing black and orange with yellow hair. If you skate up to him from the side, he will not run and scream. Instead, he will just start rolling as if he were on a skateboard. However if you try to touch him again he will fall down and scream.
Billboard
In the garage, go to entrance to 99th Street. Go to the bottom of that staircase and look to the right so that you can see a board up on the wall. If you look closely, you will see GUM and a freshly made graffiti mark on the billboard.
Go through fence
Play with two or more players on the sewer level. Jump up against the sides where there are fences multiple times. The game will glitch and you will go straight through the fence. The part where you need to jump is over the fences in the half pipes.
Timeline
When you first go into the Rokaku Expo Stadium and do the first Ball Hog mission, you can see Rokaku's weird tower completed. However, at the end of the game Rokaku mentions that it has just been finished, even though the Ball Hog tournament was two days before.
Future site of Rokku Expo Center
Begin at the start line going forward. Try to get as much speed as possible until you reach the first halfpipe. Get a lot of air and angle yourself to the left. If you have enough air and you are directly against the wall, you will slip through the crack. You can explore around the outside of the track.
Halfpipe drop-in
When grinding on the edge of a halfpipe, press the Left Analog-stick Down.
Shuffle for longer boost
The shuffle is the grind move where you press the Left Analog-stick Down. When you boost, you can use the shuffle to make it longer. You do this by shuffling at the end of the boost. You can also use it for going up objects. The shuffle is just like grinding, so you can use it to get up hills and other objects.
Avoid fall damage
Do an air combo until you reach the ground.
Shibuya Terminal: Easy Jet Tech
At the start of the level, ride the rail on the left using a Y combo. Then, turn around and ride again. Keep riding the rail until you have 200,000 and a "Jet" rank.
Rokkuku-dai Heights: Easy Spray Cans
Begin at the first save point. Grind up the rail. After getting off that rail, go up the telephone pole and grind across the telephone wire onto the rooftop. Next, jump down off of the rooftop and land on the other rail. Grind across that one. Once you get off and get to the point where there is a rail that looks like a chain-link fence with a mobile trailer, go through the mobile trailer. You will get about twenty Spray Cans and one Health Can. You will also be in another area that you can reach about five seconds more than this secret.
Hikage Street: Easy Spray Cans
As soon as you enter, go to the left and ramp the yellow cans. Instead of giving you one can, it gives you two. The more you go there, the more cans you can get. It is possible to get up to twenty cans.
Gougi and Clutch
After you get a "Jet" ranking from Rokaku-dai Heights, you will unlock Gougi Rokaku. Once you have saved the game, play in versys mode on a team. On the same team, have one person choose Gougi and another person choose Clutch. Win any mission and watch them dance the same.
Yo Yo and NT3000
Once you get a "Jet" ranking at Sky Dinosaurium Square, you will unlock NT3000. He looks like YoYo with the hood on. Once you have saved the game, play in versus mode on a team. On the same team, have one player choose YoYo and another player NT3000. Win any mission and watch them dance the same. The glitch is that NT3000 is the same as YoYo. If racing, be first as NT3000 after any lap and DJ Professor K will call him YoYo even though the scroll at the bottom says NT3000.
Noise Tank and Roboy
When you unlock the Test Run option, complete Rokkaku-Dai Heights on the graffiti, tech, and flag to unlock Noise Tank. Then, use him and talk to Roboy. When he says "What are you lookin' at?", do not press a button. Instead, watch them dance. They dance the same, revealing that Roboy is a Noise Tank prototype.
Gum and Jazz
Allow the game to idle for a few minutes and you can see that they dance the same.
Beat and Yo-Yo
Play as Beat then let him remain idle and watch him dance. Play as Yoyo and watch him dance. They both dance the same.
Get Combo
To get Combo, watch him. If this does not happen, go up to him and press R. First, grind down the ramp. When you get to the red thing, jump. Next keep grinding until you run into the huge crowd of people. Next. jump. Then, grind up the ramp. Next, jump onto the "escalator". Stop near the end. Combo will then join you.
Defeating the Rokaku Police
In order to defeat the Rokaku Police easily, try to get to the captain, trip him, and put graffiti on him. After that, go for one of the minions and defeat him. This also works for the tougher minions.
Defeating Hayashi
When you are in the battle where he is on top of the building on Chuo Street, an easier way to defeat him is to knock him off the edge of the building.
Defeating Beat
When you have to race Beat in the street race, you will get to the point where you have to copy his exact moves, grind on the rail, break through the glass, jump on both rooftops, then jump off and finish the rest of the race. You will get at least around five corners from him but you will hear his roller skates. However, if you look on your map his dot will be far from where you are. Keep going, but do not take your time or he will "boost dash" and knock you down.
Restore health
To restore your health to the maximum, go to "Garage". Your health automatically goes to full.
Easy win at Ballhog 2P
Go against Poison Jam. Get the ball, then go into the second pipe. Turn around and throw the ball. Go into the middle of the pipe and wait. Poison Jam will just stand there.
Easy Jet Tech
In each level there is a 500 point grind. For example, in any level with the green metal side walk guard gives you 500 points. If you do the back to front or Y grind combo over that same grind, you can easily get a Jet ranking.
Hidden Message #2
To find out what year the game is based in, go to the "Garage" center in the game. Go to the big stack of speakers in a pyramid by the basketball hoop. Move the Right Analog-stick for about one minute. You can now use it to look in first person mode. Look in a corner on a speaker. In bold white writing, you will see "INU-2007".
Hidden message
Collect all the Graffiti Souls and look at the square that you select your pictures on. On SS there is "be a" S is "master" M is "of" L is "the" and XL is "streets". This creates the message "Be a Master of the Streets".
All characters
Successfully complete everything in the game in under ten hours.