This Seeking Tech guide will show you how to get the Methodical Sharpshooting trophy and achievement in Metal Slug XX.
This will unlock when you meet the following requirements: “Defeat The Union’s parts in a specific order (Mission 5’s boss).”
You will need to destroy the 01 unit first. Afterwards, you need to defeat the 03 unit. Finally, defeat the 02 unit to unlock this trophy.
You can use the following video as a reference: