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