The Special Smile Add-on for Groove Coaster has 6 achievements.
Play Special Smile 20 times
Play Special Smile and clear all of SIMPLE, NORMAL and HARD
Play Special Smile and get A Rank in SIMPLE, NORMAL and HARD
Play Special Smile and get S Rank in SIMPLE, NORMAL and HARD
Play Special Smile and get S+ Rank in SIMPLE, NORMAL and HARD
Play Special Smile and get S++ Rank in SIMPLE, NORMAL and HARD