Clay Fighter 63 1/3 cheats and cheat codes for Nintendo 64

Press the following button combinations at the fighter selection screen:

Unlock Dr. Kiln as playable character:
Hold L and press B, C-Left, C-Up, C-Right, C-Down, A.

Unlock Boogerman as playable character:
Hold L and press Up, Right, Down, Left, Right, Left.

Unlock Secret Options (body sizes, backgrounds, camere acontrol etc.):
Hold L and press C-Up, C-Right, C-Left, C-Down, B, A, A. 

Unlock Sumo Santa as playable character:
Hold L and press A, C-Down, C-Right, C-Up, C-Left, B.

Programmer's mode
Hold L and press A, B, A, B, A, B, C-Left, C-Right, C-Up, C-Right, 
C-Left, C-Right. 

CPU control
Hold L and press A(5), C-Up, C-Down, C-Left, C-Left, B, A, C-Right.

Random fighter select
Hold L + R.

Change to costume colors scheme 1:
Hit A

Change to costume colors scheme 2:
Hit C-Down

Stage selection:
Choose 2-player mode, after hit C-Left or C-Right at the screen
that displays the current stage.