help with halo 3 mythic disc achievements?

[Josh]

i am trying to boost my gamerscore and
i have the halo 3 odst campain and mythic
disc i need the following:

headshot honcho
fear the pink mist
steppin razor
killing frenzy
were in for some chop
lee r wilson memorial
overkill
two for one
used car salesman
maybe next time buddy
road rage
defend this
alas poor yorick
look both ways
hammer time
pull
blades of fury
ghost patrol
post mortem
awww too bad
killtacular
have fun respawning
save this film
delicious brains
zombie repeller
tank dropper

 

[SHIRLEY.]

Most of them aren't even hard to get, if you play social with a team. Boosting will just get you banned.