Fingers Try to use multiple fingers to speed up hitting all of the unlocks, soak all the sucks and swipe away dirt at the same time.
More Ducks If you do not have enough ducks to pass through to the next area you can replay old stages and Challenges to earn more.
Special Themed Ducks New stages and special themed ducks like a gladiator and astronaut duck are earned when you complete challenges.
Power-Ups These are available throughout the game but you only receive so many for free. If you need more they can be purchased for $.99 per turn. Powerups include the Vacuum which 'sucks' water towards ducks, the Absorber which makes ducks immune to toxic liquids for one turn and the Dropper which fills up most ducks with water so they only require one drop to be picked up.
Facebook Ask Facebook friends for help before spending money getting extra energy. When you sign up with Facebook your first refill is free and you can get others easily with 'Friend Requests'.
Duck Rush Stages In these stages you will need to keep digging to prevent the water from reaching the top where it falls out of view. This is accomplished by digging as wide a path as possible so that the water remains level then dividing it up so you collect the six scattered ducks. These stages may take several attempts before you are successful but there is no penalty apart from having to refil your energy.