The one where you gotta kill the UED scientists, I'm finding this one almost impossible on hard mode, the main problem is the orange Zerg's air attack is really strong and will widdle down most my forces usually by their 3-4 attack also find it very hard to expand and not either lose your expansion base or lose your main because your expansion gets swarmed by ground units while they orange Zerg senD massive air attack to your main base.
I've tried quite a few stratigies on this mission so far, I tried going mutalisks but the 4th air attack they send devourers guardians and mutalisks which just destroy my mutas(usually I'm at about 20 then this attack kills 8-10 of them) I tried lots lots of hydras with queens for brooding but same problem oranges guardians and mutalisks eventually come in such large numbers they just rape the ground units. I thought of one final stratigey was to go hydras with defiler support, shoot a plague at the gaurdian/mutas then wait it out and one shot them all. Anyone able to come up with a decent stratigey? Really i don't have much problem till I go to expand then the AI attack waves seem to get so brutal and constant at both bases now and only have a force big enough to defend one base so I have to move it to defend against the attack(usually this is the orange air attacking my main) then by the time my force gets back to my main base to fight off the air(which at this point the air attack is very big enough to kill a decent amount of hydras) my expansion is being hit by several ultralisks zergling and hydra combos , which my now widdled down force isn't able to stop.
Also I tried episode 3(first Protoss campiagn) on brutal but the attack waves on the first mission seemed almost impossible to stop, have these missions even been beat yet?