All weapons on current level: 
     Pause the game play, then hold L and press Right, X, X, Y, X.

Slow motion:
     Pause the game play, then hold L and press Left, Down, Up, Right, X.

Invisible mode:
     Pause the game play, then hold L and press Up, Left, Right, Up, X.

Beagle holes, footprints, and burns:
     Pause the game play, then hold L and press Down, Up, X, Y, X.

Alternate lighting:
     Pause the game play, then hold L and press Up, Right, Up, Down, X.

Alternate fade:
     Pause the game play, then hold L and press Right, Up, Up, Down, X.

Fish eye camera:
     Pause the game play, then hold L and press Left, Up, Right, Down, X.