Here is the full list of all 17 Sentinels achievements.
Get your first kill from a critical hit
Kill 100 enemies
Enter gun for the first time
Get a 5 kill streak
Get a 10 kill streak
Build first automated structure.
Kill 100 fast enemies
Kill 100 enemies with combos
Kill a boss
Perform a Team Combo
Earn 1,000,000 in bounty
Kill 200 enemies with critical hits.
Get a 20 kill streak
Get 100 pieces of loot
Get 10,000 parts
Upgrade 10 items
Reach Soldier level for your gear.