She shot a grenade at it with her high-powered rifle, and then the Shivan's slaughtered everyone else with their little white blade thingies. But yeah, Shivan's would be an AWESOME foe to fight. But those weapons were ONLY 32 years old then the ones they have now. The same marine design would be neat, but you have to have more high-powered rifles in order to kick more ass. Something like a mass driver would just KICK ASS. Like a mounted rifle which fired a high-velocity slug at a target. BIG damage to a Shivan in that instance. OR, it would be something like a rifle that took 1.5 seconds to refire, but it was powerful enough to kick ass, like impale humans against the wall. We can build off this, however...