WCW Nitro
Unlock single set of wrestlers
At the options screen, press R2, L2, R1, L1(2), R1, L2, R2, Select. Then, highlight a wrestler at the character selection screen and press L1, R1, L2, R2, L1, R1, L2, R2, Select. Now all three hidden wrestlers related to that wrestler will be unlocked.
All wrestlers
At the character selection screen, press R1(4), L1(4), R2(4), L2(4), Select to unlock all forty-eight bonus wrestlers in the game. If you entered the code correctly, you will hear a sound.
All rings
At the options screen, press L1, L2, R1, R2, L1, L2, R1, R2, Select. Then, The Graveyard, Spaceship, Circus, Hive, Turbo, Wunderland, Boudoir, Hall of Mirrors, Reck Room, Psychodelic, Disco, Jungle, 1984, Quark, and Texas rings will be selectable.
Ring select
At the options screen, press R1, R2, R1, R2, Select. Then, every time Select is pressed, the current ring will advance to the next in the series. To move in reverse, press L1, L2, L1, L2 followed by Select.
Hidden rants
At the character selection screen, highlight any wrestler and press Circle to hear his comments.
YMCA dance
Select the Disco ring, and press L2. This also may be used to help win a match. Throw your opponent out of the ring and press L2 when he stands until time runs out.
Swelling heads
At the options screen, press L1(7), L2, Select. If you entered the code correctly, you will hear a sound. Then, the heads of each wrestler will swell with each hit.
Big head mode
At the options screen, press R1(7), R2, Select. If you entered the code correctly, you will hear a sound.
Big heads, hands, feet
At the options screen, press R2(7), R1, Select. If you entered the code correctly, you will hear a sound.
Big hands
At the mode selection screen, press L2(7), L1(17).
Special ending
Complete the game with one of the programmers for a special ending followed by FMV sequences for all the characters.
Interference
During a match, press Select for another wrestler to enter the ring and interfere with the match.

YMCA Dance...while in the disco ring (on all rings mode), hit the taunt button and the wrestlers ih the ring will do the YMCA dance.
(2 wrestlers in the ring = low cheer, 3 wrestlers = medium cheer, 4 wrestlers = loud cheer)

Get all hidden wrestlers
R1 R1 R1 R1
LI LI LI LI
R2 R2 R2 R2
LI LI LI LI
SELECT

BIG HEAD MODE: R1 R1 R1 R1 R1 R1 R1 R2 SELECT

ALL 24 RINGS: L1 L2 R1 R2 L1 L2 R1 R2 SELECT