Here is the full list of all 18 Infiltration: Alone in Combat achievements.
Mission 1 Completed
Mission 2 Completed
Mission 3 Completed
Mission 4 Completed
Mission 5 Completed
Mission 6 Completed
Mission 7 Completed
Mission 8 Completed
You have killed an enemy with a headshot
You have killed three enemies with a headshot
Mission 1 Completed with Honor
Mission 2 Completed with Honor
Mission 3 Completed with Honor
Mission 4 Completed with Honor
Mission 5 Completed with Honor
Mission 6 Completed with Honor
Mission 7 Completed with Honor
Mission 8 Completed with Honor