Here is the full list of all 30 Warhammer 40,000: Battlesector achievements worth 1,000 gamerscore.
Complete the tutorial
Complete Act One
Complete Act Two
Complete the Age of Crimson Dawn campaign
Unlock a flying unit
Unlock an Adepta Sororitas unit
Call in a Stormraven missile strike
Kill a Genestealer
Kill a Tyrannofex
Kill unit with a flame weapon
Heal an ally
Score a critical hit with a bolter
Score a critical hit with a chainsword
Use the interact command
Unlock a Tier 1 node in a tech tree
Unlock a Tier 3 node in a tech tree
Unlock a Tier 5 node in a tech tree
Complete any campaign mission using only melee weapons
Clear Kemrender of infestation nodes
Collect Gallian's staff
Kill an enemy unit with a grenade
Recruit a Baal Predator
Recruit a Furioso Dreadnought
Win a skirmish battle against Blood Angels
Use the fallback command
Kill a Trygon with pistol
Kill a Hive Tyrant in a multiplayer game
Kill a Blood Angels Lieutenant in a multiplayer game
Trigger the Volatile ability
Sacrifice all Death Company units at Wind River Canyon