Unlock Hen grenades:
On the code entry menu enter HENSAWAY to attack with a new selectable weapon.

Cheats:
On the code entry menu enter: 
DANGERD: Play the whole game as "Danger Duck". 
HENSAWAY: Attack with a new selectable weapon. 
AMUNKEY: $500 
PASSPORT: Access All Areas 
WEENY: Shrink Ray 
CANNON: Cannon Ball Costume 
OUTTAKE: Duck Danger Battle 
SUITSYOU: Free Costume Doors 
SLAPPY: Gives Slappy Fish to whack baddies. 
GOBBLE: Gossamer Doors Revealed 
TOUGHAGE: Invulnerability 
FURRYOUS: Wile E. Coyote Game