Mass colossi until you get void rays. Then mass void rays until you get carriers. Then mass carriers while building more cannons. Make sure you upgrade and saturate your mineral lines. Use phoenix to lift up hybrids. --- http://img704.imageshack.us/img704/297/keyboardwut.jpg
Massing Colossi on brutal? This didn't even work for me on hard. Being that they are so expensive, I had three problems when trying this:
1) I had very little resources to build air defenses or rebuild photon cannons after each wave, and since colossi can't attack air they were useless when zerg starts sending in flyers from multiple directions. 2) They are slow, and took too long to relocate at whichever choke point was being attacked currently if I decided to keep them together. If I kept them evenly distributed between all 3 chokes, there weren't ever enough of them to do enough damage before they got overwhelmed. 3) Even if I left them on the cliffs, they would be vulnerable to air attacks.
Maybe I'm just a bad player and I won't deny that possibility, but it just didn't seem like a very effective unit to me for this mission.
You can use the top left expo for more resources, but the downside if that you'll need a DT wall to keep it safe...
You can always try building cannons everywhere you can find, don't know how well that can work though. --- There are three kinds of people in this world. Those who can count, and those who can't. I survived the APOCALYPS3. 2/28/10
Well, I got over 1000 kills more then I needed on hard with this strat. Basically you're gonna fall back pretty fast, start making a decent amount of cannons. Then mass phoenixes *To lift the hybrids*. Void rays, for their great DPS. and carriers to distract. Just put em all in the middleish area. Pretty easy.