Go to the menu called "other". In there, the age you enter determines how bouncy the girls are - the higher or the more "mature" your age, the bouncier they get.
See the CG gallery
Finish team mode using 5 characters.
Big heads
First, beat the game with any girl. Then at the start screen, press and hold X, Circle, Square, Triangle, and Up.
Control the Victory Cam
To Control the camera while your character is doing the victory pose, press the green triangle button. You can use the the control pad to move the camera up, down, ect. and use the square button to zoom in and the circle button to zoom out.
Full option screen
Press start during a game and tap x and triangle at the same time.
New Outfit
You have to win in NORMAL level to get the first two outfits. Then you must win in HARD level to get the next two outfits. And then you have to win in VERY HARD level to get the final two outfits.
Unlock Bayman
Complete Story Mode with every character.
or
Complete Story Mode using any combination of characters 30 times.
Unlock Tengu
Collect 10 stars in Survival Mode.
or
Play as any combination of characters more than 200 times.
Deluxe Credits
Finish the game with every character in Very Hard Mode. This will allow you to view the deluxe version of the Credits. t'll contain new music, credits from every Dead or Alive Development team and Website Banners from fan websites.
Unlimited Lives
To get Unlimited Lives, go to the main menu, press and hold R2 then press X and Triangle. Start a new game and save it. You'll have unlimited lives thereafter.
Additional Costumes and Characters
An easier way to access both hidden costumes and characters, is to win ten rounds in Vs mode (it doesnt matter if you lose any) this will unlock new costumes for the player you are using.
If you win thirty rounds in Vs mode ( it doesnt matter if you lose any) Bayman will be unlocked the next time you got to the selection screen.
Easy kill
Start a new game and don't save it at any point. At the last boss you must hold and press R1, R2, L1, L2, start, and select all at the same time and you will have him dead in no time guaranteed.
Change Kasumi's Hair Styles
When you select Kasumi use the Circle button to select her with a Braided Ponytail. Use the X button when you select her to have her fight in a loose Ponytail.
Changing Time of Day
You can change the Time of Day by pressing the O button when selecting a stage.