Kill animals:
Hold (Command) + (Shift) + (Option) and click on an animal.
Level select:
Hold (Left Shift) while selecting the "New Game" option. Any level except for "Limbs, Heads And Smoking Craters" or "A Long Awaited Drinking Party" may be selected for game play.
Lose current level:
Hold (Ctrl) + (Keypad Minus) during game play in single player mode.
Win current level:
Hold (Ctrl) + (Keypad Plus) during game play in single player mode.