The four achievements:
Love is blind On the first level of the human campaign play till the part where the missile hits then go back to the begining.
Oh hi Kitty: go to quick match on frostbite. notice that the roof is actually a snowy mass of land. position yourself so that you can jump up on to it. very quickly run to the center and jump sstaght up. a hidden jump boost takes you there (your health drais while on the platform be quick)
I Hate Nature: Quick match on facility and go sown to the area where there is trees. use all of your ammo on the treetops.
Reach for the Moon: on the fourth level human campaign go to the extreme left where there is a jump pad. Use it. when you land shoot a few bullets up. if that doesn't work move a step to the right and repeat (will take a few tries) + this so others can see!
I would like to diasagree with all those saying Commanders friends are useless. On elimination rounds, and especially when you have zoombie allies, the make great meatshields.
triste you peobally lost all of your health. did you get hit by an monster? were you on fire? As it turns out, being lit on fire is not benificial for your health.