Guys how did you win the Purgatory challenge ? I just played it yesterday and the way i won it was very bizzare and cheesy,
I played it as Hailhead with another Hailhead AI, without superweapons
I did it this way
1) Based crawl inside the middle Epsilon base and dismantled it with neutralizers
2) Constructed a barracks inside the middle base
3) Endless swarm of clairvoiants raided the base
4) Spawned few huntresses, duplicants and Shadrays to remove all potential threats
5) Captured the base (To get Shadow ring for M.A.D tanks), Yuri himself dropped in the base twice within some time frame. Captured a refinery before he got dissolved by nanites (Huntresses were still present) and eight neutralizers melting him across the base.
6) Made m.a.d tank at my main base, stop its production at 98%, make MCV, load it up to naval transport, spin it up and i send it to Epsilons base and i shadow ringed it.
7) Deployed MCV inside enemy base, made factory inside their base, release the m.a.d tank inside enemy base
8) Eliminated entire base with single use of this unit
9) Made few queatzals and basilisks and Libra to mop up the surviving docks, Epsilon base surrendered
10) Shadow ringed m.a.d tank who happily entered Epsilons base and destroyed everything except shipyards and barracks
11) I released Resephs and Libra and her clones to mop up the surviving structures.
After that farce of odd tactics i said myself
"Common, there has to be a way to win this the fair way"
But the relentless assaults of interceptors (Who were my source of funds, Shrike nests and processors caused the interceptors to worth 300 a pop so in the end i had 114 000 dosh in reserves, thx Yuri i guess) made any assault very hard.
The really strong mind control pulse made any extended operations of siege party a hazard, the statues make any fast advance impossible, air units are useless due to the nests of interceptors. The terrain is cleverly made to drag the advance, pulses are spaced out so you have about 6 to 7 minutes between each other.
Wish the pulse atleast didnt affected robotic units and non humanoids, seeing Megalodons and Clairvoiants turning against its creators is very odd and it just adds fake difficulty and over reliance on Epic units like Centurion or m.a.d tank.