Devastator (EP)
21 Achievements
PS4
Overachiever
Get C-Ranks Or Higher - Any Mode 3 times
59.4%
How to unlock the Overachiever achievement in Devastator - Definitive Guide
Every time you complete a mode, or get killed, you will get a ranking based on your score. Higher score means higher rank. Since you have to complete all 3 modes at least once, and you also have to do at least one Elite run, this should come naturally. If not, you can replay Sector I which is the quickest mode and should be easy to get at least an A rank.