F.E.A.R. 3

Multiplayer>
-Solo Practice
Scenario- Mechanized Invasion
Difficulty- Insane

This method is probably the easiest way to get it done just run out to the Mech unit and just sit in the corner use the gun and laser and you should breeze through wave 1 without any problems. After i got it i did it again and made a video for it below.

**Note if you want to do this in solo practice you have to complete the story mode at least once to unlock insane difficulty*

FOR THOSE OF YOU WHO SUCK AT MECH FIGHTING!!
I tried doing this with the mech, absolutely can't. But I got this by choosing the Contractions level, The Commute. I picked up one yellow crate, containing the dual Uzis and the SMG. This levels first wave only contains the melee enemies, so all you have to do is keep distance, and slash 'em if they get close.

Good Luck!

I did this on Mech Invasion....insane difficultly/multi player....solo playing.

doctor lollypop's video is very good just watch where he stays in the very back right corner if your looking straight forward when you get in the mech. stay in that back corner behind that little hut/house and use the combo of rockets and laser beam, which is pretty effective on the enemies.
if u r getting hurt just pull back behind that hut/house to regain ur health. ***bonus i will was trying for this achievement and for me just hiding behind the hut and peeking out to kill the enemies i also got the "dead blind" achievement.***

Go to slo practice in multiplayer and select the level This is Suicide. As soon as the game starts run outsideand grab a weapons crate. I got lucky and got the SMG and Shotgun from one crate and one crate is all you should need. Grab your wepons and run all the way upstairs and run to he corner on the far left side that overlooks the stairs. This is your cover and camping spot. Enemies will come from below the stairs and across the way on he balcony. If no enemies are spawing run out to thebalcony u til you hear them or you hear barrier being destroyed then run back inside to your cover. This is the strategy i used doing this solo. Just make sure to watch out for Alma!