"Kill 100 enemies without dying" "Melee kill 30 enemies without dying" "Kill 100 enemies with precision shots" "Kill 20 enemies without taking damage from them" "Get precision kills with the throwing knife on hive" "Kill three enemies rapidly in one super 20 times" "Kill two enemies with charge of a fusion rifle 20 times" "Kill the knights who serve as blades of crota on the Earth and the Moon" etc