[G] Beating Brutal Campaign - Page 2

There is an area of low ground to the left of the last protoss base. You just need to get some tanks there with a spotter. The ai doesn't even really try to remove you from the low ground once you get there. I finished the mission with just two tanks firing on the building with a handful of marine/medic around them.

I think the real key is to have a good solid wall with a lot of SCVs repairing it. Walling with barracks is a good choice since you can also produce marines out of them. 4 at the right path and 2/3 at the left since one of them can block one of the entrances, and there isnt a lof of space. Use the psy disruptors or whatever they're called to slow down the enemies, I found this really important. Try to build them to cover as much ground as possible with them. Get some bunkers behind the walls and flame turrets to fill the space if you have them.
I don't think battlecruisers are a good choice, just because they're just way too expensive and get oneshotted by Kerrigan anyway while she could have oneshotted a marine instead. I didnt use the starport at all in the mission actually. I just got 2 facts and 2 raxxex (on top of the ones at the walls) each with tech reactor and started pumping 4 tanks at the time and 4 marines at the time (forget the medics, kerrigan will oneshot the marines anyway). Keep your money low, keep producing SCVs (because they'll die often), keep MULEing and make sure that you ALWAYS have 5 to 8 SCVs at each wall. This should hold the regular attacks.
For the Kerrigan attacks, you may want to use a nova during her attack or shortly after, to get enough time to rebuild. Use marines as much as possible to tank her, because she oneshots any unit you have anyway, might as well sacrifice the cheap ones. Just send 20 marines shooting at her while the tanks are shooting from long range (remember, you have 4 of them in constant production, you should have A TON of them). This works pretty well during the first two attacks where she doesnt have her matrix attack or whatever it is. That thing kills units so fast. You're gonna have to spread the marines a bit, try to not get near tanks, and micro them as much as possible to not lose 15 of them to a single matrix. It did the trick for me. Rebuild raxes in priority after her attack to get a good wall again.
You're gonna lost a ton of stuff in this mission, so don't panic and keep producing tanks, position them wisely. Repair your walls, produce SCVs, use MULEs, use novas and it should do the trick.
It did for me at the sixth try where I was really focused on doing all this. I didnt even need to retreat to the high ground for the last seconds, but my right side was getting pretty rough to hold.

Bunkers with firebats and marauders, surrounded by 2 factories with reactor and depots. 1/1 Helions blocking any opening. No turrets needed. SCVs repairing as much as space allows. You can also expand with two CCs with 5 SCVs in each and a sensor tower (gather SCVs and liftoff if they come). Don't leave any fighting unit at home during daylight (empty your bunkers too), but you may want to start walking back with slow units before your helions. Remember to repair and rebuild your defences during the day.

I walled in with around 4 bunks from the east and 3 bunks from the north. I didn't open south at all, I waited for them to open it and after that, I defended it with my mass hellions.

In the bunkers I put 2-3 firebats and 2 maras and rest is marines. I also put a few marauders in front of bunkers and in range of medics behind the bunkers to kill the infested marines. 4 scvs on both sides to repair.
After that I mass hellions. I moved out after night 2 and progressively destroyed the north than the west, the east and the south. By night 5 all that was left was their main and a few more infested structures. I was all out of minerals my main destroyed and my bunker lines breached.
After night 5 I made a desperate all in against their main with everything I had left. I barely managed to win 20s before nightfall. Won just by the skin of my teeth ;/

The most important thing to do IMO is to focus fire the infested buildings down with your hellions. Be quick and FF. Plan ahead where to attack to. When you get the message that it's 30s before nightfall, head back to your main and get repaired and prepare to defend the south gate.

It's a very hard challenging mission really.