I wasn't really sure what to do with this. I managed to finish the level by just running past all the enemies, but I feel like that wasn't the intended way to play. I thought maybe you were supposed to shoot them when they displayed the eye,and I managed to hit one of them once... I think? But then the eye never showed up again.
Also, it seemed like no matter how close or far away the enemies were they could always hit you if they had line of site. I died a whole bunch of times to that first guy in that first room, before I just decided to book it