Here is the full list of all 18 Xenon Valkyrie achievements.
You left behind Gilgacocoon
You Kill to AI MotherShip
You left behind Blackstorm Lab
You Kill to Deftos
You got the best weapon
You got the legendary weapon
You raised the sword
You left behind Ivory Tundra
You get an exemplary level
You fought to the end
You left behind Phoenix Wastes
You shopped at the store.
Fixed the Teleporters
You left behind Prime Reactor
You helped Dook
You left behind Thule Wulz Grotto
You left behind Acient Techforest
You got his blessing