Our brewery testing composition consisted of myself healing (on a priest, naturally), Megan on her druid (the tank), a balance druid, and two mages. Our character levels were all over the place, from freshly transferred 85s to level 87s.
Not exactly Donkey Kong, but Ook-Ook is a giant banana-chucking monkey. Ook-Ook has a pretty fun mechanic that enables players to jump on top of barrels and direct where they go. He has a few friends that are busy. If the barrels make contact with you, you'll explode and take some damage (Brew Explosion). Don't worry -- it's not lethal. Ook-Ook Goes Bananas at 90%, 60%, and 30% intervals. He starts throwing some bananas around; they're harmless. His attack speed goes up, and he hits a touch harder. You'll see a wave of barrels coming in, so either dodge them or jump on them.