GHOST 1.0

This can be done on any difficulty but requires that you chose the tutorial at the start of a new game. Without being harmed means that you can take NO damage while inside your main body throughout the entire tutorial. This basically means that you can't get hurt by a single enemy projectile or melee. It's not too bad except for the few robots who have guns. Any damage you take while inside another robot doesn't count btw. Just damage to your main rig :)

The best thing you can do to earn this achievement is SAVE AND QUIT after each room (by going to options->save and quit) that way if you do take damage you can just EXIT (without saving) and redo the room until you get it right.

The melee robots take 3 shots to kill, turrets also take 3 and the robots with guns take a whopping 6 shots to take down. The melee robots can be gunned down with ease and you can use "hit and run" tactics on the turrets fairly easily but there are 2 robots with guns that you have to fight before you get the hijack ability that will prove troublesome imo. Hit and run tactics will work on them but with their pinpoint accuracy it may take a few tries before you can beat their asses with no damage. Once you do get the hijack ability there will be another pair of robots with guns that you have to take out. Hijack one and try to take out the other one while simultaneously trying to get it to ALMOST kill you. that way when you hop out of hijack you can just shoot him down instantly. I'd like to note that if you're doing survival mode you do get a grenade add on that makes this second encounter much easier since you can just lobe some nades down.

There are also 2 alarms that you have to complete as well, one that is purely melee enemies and another than has melee enemies, the flying saw things and some single shot turrets. For the second one, try to use the platforms as cover from the turrets while you work on the fodder below. Occasionally try to take out a turret so you don't get overwhelmed with bullets flying everywhere.