This achievement requires that you use the robotic hand (only found in World 6) to catch a flying rocket 50 times. This can most easily be boosted on Level 6-23. From the start, tap the rocket and let it fly down and be caught by the robotic hand below. Instantly restart the level and repeat until the achievement unlocks. It will only take a minute. This achievement requires you to progress farthest through the game. Remember, in World 6 you can pause every level and skip to the next. You especially do not need to worry about any stars at this point.