Tony Hawk's Underground Cheats for GameCube

At the 'Options' menu select 'Cheat Codes' and enter these passwords without the quotes to unlock the corresponding feature which will make the game a lot easier. Except for the T.H.U.D. Playable character cheat you can alternatively unlock the cheat by getting ALL 129 goals.
Unlock Perfect Rail Balance:
Enter 'letitslide' as a code.
Unlock Perfect Manual Balance:
Enter 'keepitsteady' as a code.
Unlock Perfect Skitches:
Enter 'rearrider' as a codes.
Unlock Moon Gravity:
Enter 'getitup' as a code.
Unlock T.H.U.D. As a Playable Character:
Enter 'NOOO!!' as a code.

These are unlocked by collecting either Letters or Tapes or by completing the game on the indicated setting.
Unlock Kiss Concert FMV:
In the 'Hotter Than Hell' level collect ALL the letters that spell K-I-S-S. When you have them ALL this will unlock the Kiss FMV sequence. To play the Kiss concert you must collect the K-I-S-S letters again.
Unlock Bails 1 FMV:
Collect 3 secret tapes to unlock the 'Bails 1' FMV sequence.
Unlock Bails 2 FMV:
Collect 6 secret tapes to unlock the 'Bails 2' FMV sequence.
Unlock Always Hard FMV:
Collect 9 secret tapes to unlock the 'Always Hard' FMV sequence.
Unlock Lost Footage FMV:
Complete the game on the 'Too Easy' and 'Beginner' difficulty settings to unlock a new 'Lost Foo..

These playable characters are unlocked in the game when you complete Story mode on a certain difficulty setting or find ALL the Gaps.
Unlock Gene Simmons as a Playable Character:
Complete Story mode on the Normal difficulty setting.
Unlock Iron Man as a Playable Character:
Complete Story mode on the Beginner difficulty setting.
Unlock Pedestrians as Playable Characters
Find ALL the Gaps in the game.

Complete 'Slamma Jamma' in Story mode to unlock Create-A-Deck mode which allows you to design the graphics for your board.

Complete Story mode to unlock the 'Hotter than Hell' level. This level is based around a stage that is set up for a KISS concert. In this level you will find the final secret tape.

Perfect rail balance
Select "Cheat Codes" at the options menu, then enter "letitslide" as a code. Alternately, get all 129 goals.
All FMV sequences
Select "Cheat Codes" at the options menu, then enter "digivid" as a code to unlock all FMV sequences.
Cool Specials
Get all 129 goals.
Kid Mode
Get all 129 goals.
Rollerskates
Get all 129 goals.
Flame
Get all 129 goals.
Always Special
Get all 129 goals.
Perfect Skitch
Get all 129 goals.
Perfect Manual
Get all 129 goals.
Moon Gravity
Get all 129 goals.
Hangar level
In the Moscow level, find the place where there are a lot of tanks and a building that reads "AEHNH". Stand..

UNLOCK T.H.U.D.----------------------------------
Enter the word "NOO!!" as a code to unlock T.H.U.D. or beat the game on sick difficulty
MOON GRAVITY--------------------------------------Enter "getitup" as a code
PERFECT SKITCH------------------------------------Enter the code "rearrider"
PERFECT MANUAL------------------------------------Enter "keepitsteady" as a code
PERFECT GRIND-------------------------------------Enter "letitslide" as a code

At the main menu, go to options, then select cheats. Enter NOOO!! as a password. There should be a deep WHOOSH! sound to confirm the code. Go to free skate or whatever and T.H.U.D. should be the last character. GAMECUBE ONLY!!!

When you get 129 goals for tony hawks underground, put everything on except for moon gravity and rollerskates...when you did that go onto and long rail and do a mactwist on the rail, make sure you have cool specials on, so when you did that you should have cool special on until you do another special move...so it is most likely to be called slow motion mode lol.

Its not a specific glitch, but it's what it's most like. Put in getitup for moon gravity and get off your board. Now with this if you want to get into a hard place normaly almost impossible to get to. Just (after off your board) walk up to the wall by the place you want to go, and continuisly press a while walking into the wall and you can jump up the wall untill you reach the highest point in the level.

Hold buttons: Start + B + X

to have moon gravity you have to type in "getitup"

First you need the moon gravity* cheat and have it on. Second you need to be in Manhattan in Jp**. You need to go up the ramp NEXT to the elevator to the lounge. If you go high enough you'll be in midair but you'll still be able walk and skate. *The code for moon gravity is getitup.To register it go to the main menu and select options. In options select cheat codes. There will be a keyboard. Type in the code.
To activate the cheat go to the pause menu and select options. In options select cheats. There will be a screen with the name of the cheat and a switch to turn it on or off. Scroll on it and press A to turn it on.**Jp is the only building in Manhattan that you can go inside.

Hi,yo to punch Eric in the last chapter.Press B to punch him when he holds up the tape and you also beat the game but don't do it when you go to options and watch the videos.
It is AWSOME it does work.

See, Me and my brother were searching up cheats for Tony Hawks Underground. We found 'digivid' and 'gidvid' but they wont work! So try these
Moon Gravity is Getitup
A VERY long Sketch (riding on the back of a car) The cheat is 'rearrider'
Okay, The Perfet Rail cheat is 'letitslide'
Perfect Manual is 'keepitsteady'
Did I forget any cheats? Yes, I probably did, but these cheats are all I know.
Secret Tapes are probably already done in another cheat. Just check a few cheats up, or the first page. or the top or whatever.
The Game story mode is, halarious, very fun, tricky, and sometimes you will get mad at it and smack your controler against the wall.
The first level is New Jersey, I set all my highscores..

How do I get the secert level in moscow?

Like the name says, this lets you jump up buildings!
First, beat the game and all of the objectives(I did it on normal mode) and you should unlock a cheat menu that has stuff like "Cool Specials, Flame, Perfect Balance, Moon Physics,etc.
"You could also probably input codes(you dirty CHEATER!)Anyway,turn Moon Gravity/Physict on and get into walk mode and run to a wall, building,or anything like that.Then, jump into it and hold jump, and you should just keep jumping until you reach a certain point or let go of the jump button.NOTE:Sometimes, it may make you do a caveman into a trick or manual. It happens to me a lot.

Perfect Balance
Letitslide
Perfect Manual
Keepitsteady
Perfect Skitches
Rearrider
Open All Videos
Gidvid
Moon Gravity
Getitup
Unlock Thud
NOOO!!
Cool Specials
Get all 129 goals
Kid Mode
Get all 129 goals.
Rollerskates
Get all 129 goals.
Flame
Get all 129 goals.
Always Special
Get all 129 goals.
Perfect Skitch
Get all 129 goals.
Perfect Manual
Get all 129 goals.
Moon Gravity
Get all 129 goals
Perfect Grind
Get all 129 goals

To do this cheat you must have cool specials on you can get it by beating all the goals on any difficulty. Turn cool specials on and do a kickflip underflip but before the move is finished start grinding and then jump off to turn this off just do another kickflip underflip

Happy cheating!!!!

NOTE: YOU MUST HAVE MOON GRAVITY UNLOCKED TO PERFORM THESE!
(1) In Manhattan, go to the building where 78 Water Street is. It should be a brown building. Go up the escelators that lead into the back area, where you use a boneless to jump over the little wall.
Look at the building on the right.Jump up, and go to the corner,then keep pressing the A button while pushing yourself against the wall. This should make you jump more than normal. When you get to the little bridge (this is how you will know you're in the right spot), go to the end of the buiding without falling down.
Keep jumping to the very top, and jump over the limit of the buiding. If done correctly, you should be on the "roof" inside the buiding,floating.
(2) Go to the little blue buildi..

To get all your skaters on infinite stats, either.
1) Complete the game with a noob skater and get full stats
2) copy a full stat skater from a friend's memory card on to yours
After you do either of those, go to create skater, and choose to edit the full stat skater you have, change the name gender or what ever else you want to, then edit the skater look if you want, then save the skater in a new slot, and Bob's your uncle.
You have another maxed out skater, you can do this as many times as you like, you can also use the skater in story mode to beat the game easily! (you won't see this hint any other place, I came up with it my self ages ago, and have finally decided to submit it, so if you go giving this hint to other sites, please mention my name ..

To do this cheat you have to have the cheat cool specials, you get that by beating the game with all the goals.put it on too easy and activate the cool specials. Then do a kickflip underflip, when you are in slow motion during the trick grind something and you will be stuck in slow motion. To get out of it you can either wreck or do another kickflip underflip. There you go