Bianco Hills Extra Lives:

After you complete episode 3 (The Hillside Cave Secret), go back into Bianco Hills and choose episode 4. Instead of doing that episode, go back to the hillside cave. This time you do not lose FLUDD. There is a secret level up there, where if you press the red plunger you have to collect red coins in the allotted time. Do not hit it. Simply go up to the first wood platform with nails and Ground Pound the right nail three times until the 1-Up appears. Then, using the Hover Nozzle, make your way toward the end of the level. You will see the second 1-Up in the air above the second star. Use the Hover Nozzle again to get it without worrying about your step. Then, simply fall and die. Since you collected two 1-Ups, you will have a net gain of one 1-Up, The game starts you at the beginning of the cave, where you can repeat this as many times as desired to build up your extra lives. Once you get used to it, this will take about 30 to 45 seconds each time. When done, you can either do the red coin deal (gives you a Shine), or jump to the non-lit Shine to exit. Since you did not die, this time you will have a net gain of two 1-Ups.