TapMonster

"Notice their cute shapes? They have big eyes and long bodies, and—most importantly—they come in various colors. Each little creature moves in the direction its head is facing. If a creature's head is blocked by another, tapping on it won't work; it can only move forward if its path is completely unobstructed. You can drag across the screen to change your viewing angle and get a better perspective, helping you decide the order in which to move them."