Completed FRONTLINE without killing anyone
Metro 2033 Redux INVISIBLE MAN – Achievement / Trophy Guide
You have to stay undetected for the whole chapter. If you get spotted, return to the main menu and start the chapter over. Loading a checkpoint won’t work.
It can happen that enemies shoot each other when you get seen, so try to avoid it altogether and move silently. The AI is very forgiving on normal to put it nicely, at times you can walk literally right in front of them.
At the start, make your way down the pipes into the radioactive lower level and disable ALL 4 TRAPS (1:27). You will come across a guard that’s holding some red’s in a CELL (2:31). Knock him out to make sure that he doesn’t kill them. This is necessary for the Achievement/Trophy. Back at the TOP LEVEL (3:05), turn right, walk past the guard and sprint through the small way on the right side. Keep sprinting and hide in a corner on the left until the car has past you. Take your time at the last part and stay in the shadows to get to the final two doors.