Tony Hawk's Pro Skater 2

Perfect balance
Press Start during game play.
Then, hold L and press C-Down, Right, Down, C-Left, C-Down, C-Up, C-Right, C-Left at the pause menu.
The screen will shake to confirm correct code entry.

Flight mode
Press Start during game play.
Then, hold L and press Right, Up, C-Down, C-Up, C-Down, C-Left(2), C-Right at the pause menu.
The screen will shake to confirm correct code entry.
Press Ollie to hover and the D-pad or Analog-stick to change
directions.

Unlimited specials
Press Start during game play.
Then, hold L and press C-Left, C-Down, C-Up, Right, C-Right, Right at the pause menu.
The screen will shake to confirm correct code entry.

10X points multiplier
Press Start during game play.
Then, hold L and press C-Down(4), C-Left, C-Right, Right at the pause menu.
The screen will shake to confirm correct code entry.

Set stats to 10
Press Start during game play.
Then, hold L and press Down, Up, C-Up, C-Left, Down, Up, C-Up at the pause menu.
The screen will shake to confirm correct code entry.

Set stats to 13
Press Start during game play.
Then, hold L and press C-Down, C-Right(2), C-Up, Up, Down, Right, Left at the pause menu.
The screen will shake to confirm correct code entry.

Thin skater
Press Start during game play.
Then, hold L and press Left, C-Right, Right, Down, C-Down, Up(2) at the pause menu.
The screen will shake to confirm correct code entry.
.
Note: Repeat this code to increase its effect.

Turbo mode
Press Start during game play.
Then, hold L and press C-Left, C-Down, C-Up, Down, Up, Right at the pause menu.
The screen will shake to confirm correct code entry.

Maximum turbo mode
Press Start during game play.
Then, hold L and press Down, Left, C-Up, C-Down, C-Left, Right, Up at the pause menu.
The screen will shake to confirm correct code entry.

Slow-Nic mode (slow motion tricks)
Press Start during game play.
Then, hold L and press C-Up, Down, Left, C-Left, C-Down, C-Up, C-Right at the pause menu.
The screen will shake to confirm correct code entry.

Simulation mode
Press Start during game play.
Then, hold L and press Left, C-Right, Right, Down, C-Down, Up(2) at the pause menu.
The screen will shake to confirm correct code entry.

Skip to restart
Press Start during game play.
Then, hold L and press C-Left, C-Down, C-Right, Down, C-Up(2) at the pause menu.
The screen will shake to confirm correct code entry.
Alternately, successfully complete the game with Bucky Lasek.

Extra money
Press Start during game play.
Then, hold L and press C-Left(2), Up, C-Right, C-Up, Down at the pause menu.
The
screen will shake to confirm correct code entry.

Double moon physics
Press Start during game play.
Then, hold L and press C-Down, C-Left, C-Right, C-Left, Up, C-Down, Down, Right, C-Down at the pause menu.
The screen will shake to confirm correct code entry.

McSqueeb
Get a 100% completion in career mode as Tony Hawk.
Select Tony Hawk's third costume to play as McSqueeb.

Spider-Man
Get a 100% completion in career mode as a created skater.

Officer Dick
Mark half of the gaps in the normal levels as discovered to unlock Officer Dick.

Trixie
Mark all of the gaps as discovered to unlock Trixie.

Skate Heaven level
Get a 100% completion with all skaters.

Mat Hoffman Bike Factory level
Get a gold medals with every character (including a bonus skater) except for Trixie.

Tony Hawk's special moves:
The 900: Press Right, Down, C-Right.
Sacktap: Press Up, Down, C-Right.
Overturn Grind: Press Down, Right, C-Up.

Hints:

More speed
To get more speed, hold A or C-Down.

Get up faster
Rapidly press Up and Down when you fall down to get up faster.

Selecting career mode levels
When you are on a level that needs to be unlocked it in career mode, go to the level to the right or the left of it.
Then, quickly go back to the level and immediately press A.

Easy 900s
Get your special full, then ride up to any quarterpipe with a fair amount of speed.
Do a Boneless for big air and then
press the buttons to do a 900.
You will land it almost every time.

Skate in pungee pits
In any level with pungee pits, grind on the edge and purposely crash towards the pit.
If done correctly, you
should be able to skate around in the pit.
To get out, wall ride and try to jump out.

Bullring: Smelly money
Ollie into the bull pit and skate through the bull's droppings to get most of the money.

Marseilles: Endless grind
Begin game play in the Marseilles level with the "Perfect balance" code enabled.
Jump onto the a circle in the front going slow and grind.

Marseilles: Secret area
When you start, skate over to the wood wall with the green spray paint.
There will be a street light near it, in the grass.
At the bottom of the light is a piece of wood holding the light up.
Skate through the piece of wood.
The light will fall, knocking a hole in the fence.
Go through this hole and down the hole in the ground.
You will end up in a room where most of the cash icons are located.
There is also a cool fountain in the middle.

Philadelphia: Money
When you start, make a left until you get to the stone benches.
You should be able to see them when you turn left.
Turn right and go all the way down, past the stone benches.
There should be a house directly in front of you.
Go up the
balcony on that house and grind the telephone line that leads from the balcony up to the top of the pole.
You need to grind up almost the entire length.
When you do, the poles will fall and knock down the fence gates near them.
Go in there to find a small skate park.
It contains cash icons that are scattered about.

School 2: Open the swimming pool: -  When you start, skate down the corridor, then at the end turn left.
Down there will be some steps with a rail on them.
Grind that as the second bell rings and you will be able to go into the swimming pool located in the building with the suspicious looking doors after you drop from the starting location.
Note: Grind the rail as soon as you see the security guard going up the ramp on the right.

School: Open the gym
Skate down the Roll Call! Nightmare Fall rail (the very big one) when the second bell is ringing.
The blue text indicating that you have found a secret gap will appear.
Skate over to the gym.
The door will be open, allowing you to go inside.