I finished the campaign, replaying the brutal/hard mode. (don't wana invest on multiplayer just yet..)

So anyone has any tips on how to get the achievement in the mission "Zero Hour"? It just seems impossible that I have to destroy 4 hatchery with only marines and medics....

I youtube'd it and apparently, we just need to mass Marine & medic. The guy on the video didn't even micro....I guess i will try it out now, I just don't have enough patience previously.

You guys talking about the last mission right?

Tychus (take out land) - Fun mission but suffer later....
General Warfield (take out air) - Boring mission but enjoy later...

Reason why i say having no flying zerg is better is because you don't have to worry about broodlord coming from the back. Even if you go with Tychus...you still get attacked by land unit, just lower volume. So basically if you choose Tychus, it simply means you have to defend both land & air units.

The trick to beat the last mission (All In) on Brutal or hard difficulty is to concentrate all your units in the middle (near the Mercenery building) You only need a couple of things :
1. Siege tank. LOTS OF THEM. Like at least 60% of your population.
2. Lots of marines, please reserve the number until Kerrigan appear. They are basically the bait for Kerrigan to shoot at, instead of letting Kerrigan one-hit-kill all your powerful units (eg. Tanks, Battlecruiser)
3. a few Science Vessel & SCV just to repair the stuff.
4. If you have research the little building that slow down the zerg...the game would be alot easier.