How I personally ended up doing it: if you notice, the very top left and top right spots will NEVER get hit by his tentacles. I would put all my primal hydras and roaches in either corner and have them attack Zurvan. You can not fit all of your roach/hydras into the top positions, but at least 50% of them will not be attacked by Zurvan until the final stage. When they are hit, move Kerrigan up and use your
Mend spell to heal her and your roach/hydra/ultra.
The safe spots are circled in the blue (screenshot taken from PsyStarcraft replay, see first comment on question for link)
I would then micro Kerrigan and the Ultralisk to both kill minions, and to attack Zurvan as much as possible. When minions came up, I would use Kerrigan's special abilities to burn them down while the roach/hydra took down Zurvan. It's also important to use Kerrigan to group the minions together, and use
Psionic Shift to attack as many as possible. When the acid spewers are summoned, make sure you burn them down first (they will spawn in a group of 2 with an ultra) as they will two shot your hydra/roach if you let them get attacked.
At the final stage (roughly 10-15% life), I only had the Ultralisk and Kerrigan alive. I was able to defeat Zurvan strictly with them and eventually with Kerrigan only. With her spells she can solo Zurvan alone. I used
Leaping Strike and
Psionic Shift to mainly get out of the way of Zurvans Attack and to burn the minions down faster. And
Mend was used as much as I could get away with it, to keep Kerrigan topped off in case I would slip when microing.
Picture of the last stage where Zurvan uses a cone shaped attack. This is where I used
Psionic Shift and
Leaping Strike mainly as evade and for burning minions. (screenshot taken from PsyStarcraft replay, see first comment on question for link)
I also beat it all on Brutal, and he was my biggest test. It would take me about 5 attempts, but after I started microing better I was able to take care of him. Hope it helps :)