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