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