Melody is a type of Challenge in Where's My Water? 2. In this challenge, Ducks are replaced with five colored musical notes that take three drops of their respective Fluid to fill. The fluid is dependent on the Character in the level and each note requires only three drops rather than the usual five with Ducks. Plus, the colored notes must be collected in the correct order and the correct fluid from left to right: red, orange, yellow-green, light blue and pink. When collected in the right order, the notes will play the first five notes in the A major scale.
A noticeable difference is that the notes when collected sound like a piano instead of Allie's Organ.
It is the fourth challenge in this game, which is introduced at Level 15 in the Soap Factory.
There are three specific ways to fail a Melody Challenge:
If a note is skipped and the wrong one is even partially filled, if all five notes were not collected, if you let the wrong fluid fill up a required note for the required fluid to pass (such as in a Swampy level, when a drop of Purple Water tries to fill up the first note when the regular Water was supposed to collect that note starting up the level), the level is failed and the player must have to start over.
Also, even if you have collected all the notes but do not have enough required fluid to pass the level, the level challenge is still failed despite the fact you have collected all five notes (with some exceptions such as level 17 or level 27). This can only occur if you let the required fluid (such as water to Swampy, steam to Allie, or purple water to Cranky) run out.
The first note that appears in-game is a crimson red, the second note is a generic shade of orange, the third note is more of a shade between yellow and green, the fourth note is a light blue, and the fifth note is a slightly lighter shade between pink and magenta. This is also true in the original game.
However, in the game files of Where's My Water? 2, a sixth note that has common shade of purple exists but is currently unused.
The sprite for the music note were initially colored white by default, but are recolored using a specific hex value as follows:
The red note uses the hex value #B73434.
The orange note uses the hex value #ED9E40.
The yellowish-green note uses the hex value RBG #C3D600.
The light blue note uses the hex value #96C6E8.
The pink note uses the hex value #D155AE.
The unused purple note uses the hex value #6B3592.
The Melody Challenges were created by David Goodrich, the Lead Designer on WMW2.