Quantum Theory

To unlock this achievement, you must simply destroy one watcher. After the short intro, you will team up with a militia group that is assaulting a new tower. After leaving the building you start in you will fight some enemies. After a short while, the game will go into a quick cut scene that shows a floating green orb above a looming battle. This is your first watcher, simply destroy it to unlock this achievement.

I hope this solution helped! Leave a comment letting me know if there is any room for improvement! Thanks.