Here is the full list of all 20 Terminal squad: Sentinel achievements.
Complete 10 tasks
Spend 120 minutes in battle.
Complete level 50.
Collect 100 000 credits.
Kill 1000 enemies.
Spend 60 minutes in battle.
Complete level 10.
Deal 1000 damage.
Spend 30 minutes in battle.
Kill 100 enemies.
Collect 1000 credits.
Complete level 100.
Complete level 200.
Complete level 300.
Complete 20 tasks.
Complete 50 tasks.
Deal 100 000 damage.
Deal 100 000 000 damage.
Kill 10 000 enemies.
Collect 100 000 000 credits.