This achievement requires that you finish the level scoring between 0 and 100 bonus points. Bonus points are what you are awarded when you complete the level, and are shown in the top right corner of the screen. Each level has a maximum number of points possible which depletes as you take time to complete the level. Essentially, you just need to complete the level so that the shrinking score in the top tight corner is less than 100 and greater than 0. This requires some luck and also good timing. The easiest level to attempt this on is Level 1. You do not have to worry about missing this achievement, because you can always just start up a new game at Level 1. Use the only object you get to direct the drops near the mouth of the container, but not in. Just leave it like that, holding your finger on the object to keep it from moving. When the bonus score reaches around 750 points, rotate the object and direct the drops into the container as fast as you can. If you got the timing right, 40 drops will fill the container, completing the level, and your score will be in the right range. This will likely take several tries to get the timing and method exactly right. Just keep at it.