Play as Poison:
Type Poison at the "1) Player 2) Players Q)uit" screen. 

Clue Mode:
Type Akces at the "1) Player 2) Players Q)uit" screen. 

Hidden Options:
Type IKE at the "1) Player 2) Players Q)uit" screen. Sound, access to Poison, and clue mode
options will become available. 

Enable background colors:
Type ifokvision at the "1) Player 2) Players Q)uit" screen. 

Exit game:
While in game play press Esc. 

Jump up and left five spaces:
Press the special jump button, 2442, and the special jump button again during game play. 
Random Select:
Press Tab when selecting a character.