I've played quite a few 2v2 games now and started moving up to the Hard AI in 2v2. I do fine as long as I go Terran, but as Zerg I'm having real trouble. I find that I have 2 weaknesses in my gameplay:
1) initial rush survival. I can't make zerglings or lings/roaches do well against the computer. I haven't tried going zergling/banelings yet, but even on medium AI unless i have burrow I don't seem to be able to use my banelings effectively. Going hard spine crawlers is difficult because of lack of early creep production.
2) transfer to late mid-game. When I do manage to survive the initial rushes (usually due to a really effective companion) then I'm having trouble getting into an effective late mid game and end game. I've been really effective against the ai with harassing mutalisks, especially since you can get the AI to ping-pong their troops, but microing that harassment while keeping my economy going and teching up to t3 units is giving me problems. If I go heavy hydras then I essentially have the same problem. I do ok until the computer techs up enough that mass hydras just aren't cutting it anymore, then I find myself behind on the tech and economy race. What t3 units complement a hydra-heavy build?