I’m sure many of you with experience in playing Co-op have had memorable extraordinary games with extraordinary allies (for better or for worse). I’ll tell some of mine.
Blessed Games
Chain of Ascension. Me as low level Zeratul, ally as Mastery Mengsk P3.
Knowing how Mengsk P3 mass infantry can be a deadly, yet resource hungry force, I offered my ally to take my expansion and go pumping from three bases. Worked like a charm — I’ve been wandering around the map with <10 units all the time, while the ally had a huge force of deadly soldiers rigged with explosions following me around. After winning they gave me the credit for planning all this, despite the fact they were the one who carried us to victory.
Void Launch, weekly brutation. Me as Mengsk P3, ally as Stetmann P2.
As far as I remember, that brutation came with “Going Nuclear” and some other movement hindering mutators, such as “Blizzard” or “Time Warp”.
Seeing nukes all over the place, I’ve been sceptical about my ally having P2. Asked him whether P1 is a better option, to have unbreakable stetellites. He responded with a mysterious Gary smile…
However, later on I’ve bared witness how they moved Super Gary and the stetellites all over around like if there were no nukes at all! And they had zero worries about their army too, as they massed Mecha-Infestors at home throwing constant stream of Roaches+Ravagers towards the enemy spawn points. And because our enemy was zerg, it all turned into a one giant mess 
Meanwhile, I did my Mengsk thing as usual — mass propaganda, mass recruitment, mass mobilization with explosive arms. While my ally kept enemy busy with his paper roaches, my suicide squads were sniping objective after objective. Truly enjoyable.
Oblivion Express, me as Swann, ally as Vorazun. Prestiges were not a thing back then.
So, I did my usual Swann thing on this mission — mass turrets + tanks on both railway “bottlenecks”, more than enough to derail any train and stop any attack wave. My ally, though, was something else. They placed Dark Pylons in all different tactical positions for either intercepting enemy attack waves or enemies wandering around the map, then recalled my Siege Tanks right in the spot to efficiently shoot at enemies from high range. Shortly before the game ended they game me a mysterious wink 
and left, leaving the map full of Siege Tanks all over the place, positioned exactly in a way to kill everything and anything and allowing to finish the mission while being AFK.
Cursed Games
Mist Opportunities, me as Tychus P2, ally as Artanis P0.
Playing as usual, I sent my Big Dudes to delete everything on the map, in many directions.
My ally suffered big losses because they have gone mass Tempests and got hard-countered by the Air Terran enemy. However, that didn’t impact our progress — Tychus P2 is just that OP.
Well, it seemed like my ally got pissed, because in the middle of the mission they just sent all their forces on Move command to die, then sent all their probes to die and then left the game. I didn’t even know, what the hell was that about.
Void Launch, me as Raynor, ally as Nova. Prestiges were not a thing back then.
After I got used to Raynor’s mass Orbitals with mass MULEs, I liked the playstyle of giving my expansion to ally and going mass infantry — with mineral sulprus from 1 base I have just enough resources to max out with all upgrades, assuming I’m not taking big losses.
And so, here how it was on this mission:
Me: wanna take my expansion?
Ally: you need your expansion
Me: no, i don’t
Ally left the game!
Well, screw it, I left too. And tried to calmly explain them, why exactly I’m OK with 1 base on this commander. Response? No, got blocked right after my 1st message. They didn’t even want to hear what was I about to say.
Chain of Ascension, me as Mengsk P0, ally as Artanis P0
As usual for pre-P3 sub-mastery Mengsk, early game is painful. Though I was able to defend against the attack wave and also defend Ji’nara from rolling back (all alone), it was at a cost of big losses. My ally was suffering losses too — lost 1 Dragoon here, lost 1 Dragoon there…
Enter the Hybrids, Ji’nara is screaming for help. And the ally is pinging to push the hybrids. I mean, sure, but I need to reconstitute my forces after killing attack wave after attack wave after attack wave. All alone. “Where are ally’s forces anyway?” — I thought, — “Throughout the mission I’ve only seen 2 Dragoons so far!”
So, I looked at their base… and there were more than ten Warp Gates. On a single base. Guess it’s no wonder the mission was lost shortly after.
