Press Start to pause and enter the following:

Freeze computer - Left, Left, Up, Down, R2

Extra damage - Up, Up, L1, L2, Down

Little damage - Down, Up, L2, Right, Left

No damage - R2, L2, R2, L2, R1

Charge Combo Meter - R1, L2, R2, L2, Right

Auto super-pins - Down, Down, Down, L1

Super Pins:
Enter after winning your 2nd round when it says "PIN HIM"

HBK Shawn Michaels: D, UP, SK, SK, P
Vader: D, U, K, K, K, K
Bret Hart: D, U, SP, D, U, SP
Owen Hart: D ,U, P, P, K, K
Ahmed Johnson: D, U, P, SP, SK, K
British Bulldog: D, U, P, SK, SP, K
Goldust: D, U, SK, D, U, SK
Hunter Hearst Helmsley: D, U, SP, SP, SP, SP
Ultimate Warrior: D, U, P, P, P, K
Undertaker: D, U, SK, SK, SP, SP

Bomb Squad Enterprises:
Any time during the game pause it then press Down, Down, Down, Down, L1