Here is the full list of all 16 The One We Found achievements.
You Have perished 20 times
You have destroyed the horde
You have Completed Level 1
You have Completed Level 2
You have Completed Level 3
You have Completed Level 4
You have Completed Level 5
You have Completed Level 6
You have Completed Level 7
You have Completed Level 8
You have discovered the secret
You have destroyed a melon
You have killed a past patient
He didn't deserve it
You have Completed Level 9
You have Completed Level 10