Side-scrolling mech-shooting bad-assery is BACK! GIGANTIC ARMY is a heartfelt homage to 16-bit era mech shooters such as Cybernator / Assault Suits Valken, Metal Warriors, and Front Mission: Gun Hazard, developed by the studio behind the acclaimed shooter SATAZIUS.
Resolved: "Only for the Hardcore" Achievement not Unlocking
Issue has been resolved. If you had previously unlocked Insane, completing any level on Hard should unlock the achievement.
Strangely, the achievement for unlocking the Insane difficulty didn't trigger when I 1CCed hard.