oh yeah, finally beat the ship at the drill platform mission on hero mode and it's clear coasting from here on [although i walked directly into the retrieve the seal piece water slums mission not long after, ahah]. some tips for the fellow hero mode challenger struggling with this; memorize the appearing locations of the first seven krimzon guards, get them fast. if any guard is close to you wait, aim, then fire, if you constantly fire you run the risk of clipping them ineffectually and having them drop down to return later. when you hit a guard, track their movement as you fire, moving the crosshairs to the side or up will nail them even if they do bounce without taking hits, and finally if you've cleaned up the closer guards always shoot those in the distance before they reach you. best of luck and keep trying.