I'm still going through the campaign but I stop to try to beat The Outlaws under 10 minutes for the achievement. I just got 10:10 which pissed me off. I tried an 8 rax strat, but it takes too long. The most efficient seems to 5 rax + bonus rax and 4rines/2 meds per cycle with rally set to frontlines. However, I keep getting 10-11 minutes. Anyone get the achievement on Brutal?
I managed this on Brutal, it took 3 or 4 attempts though.
1st completion of missin was a 20min slog
then got 2 around 11mins before getting a 9min completion
I went with 2 barracks, upgradeing to 3 soon after
1 with tech upgrade
1 spams medics, rest spam marines
I also build 7 additional SCVs immediatly
I use my starting marines to go north and grab the bonus resources immediatly - this way I am constantly building units throughout the entire game
I use 2 SCVs at the start to build, 1 for extra barracks and gas mine, 1 to extend my unit cap.
when my unit cap far outstrips my units I build the 3rd barracks (by this point I have already got the rebel barracks.
once the 3rd barracks is built is about the start of my main assault.
Basically I start attacking after about 4mins and dont stop until finished, brutal is nasty, remember to take out the siege tank asap in their base.
I mine mostly crystals, only 3 scvs for gas.
by the end my barracks are all queued up to max on production. (I shortcut my barracks so that I can select them quickly and top up the queues) and I still have >1000crystal.
in the enemy base remmeber the siege tank at the back, he destoys my army very quickly if Im not careful.
I also tend to ignore medics, with an army it is better to take out the marines 1st, they die in under a second each, medics dont have time to switch and heal them
focus fire attack
remmeber destroy barracks 1st, ignore the additional side structures till the end(medic bay and the operations thingy)