In the Ilomilo minigame, on the Byte Seyes, you'll have to control two little character at the same time, on the small map. Parts of the map will move, either it being in a line or in a column. If it goes too far, the end of the line or column will disappear. If one of your character stands on it when it disappear, he'll fall and it's game over (otherwise, your characters doesn't fall when you move them toward the border of the map). Your goal is to gather kind of pictures or some little characters that appears randomly, and reach 500 points to get the achievement.