I keep getting my clock cleaned by the Collector. I slime the mask, yank it off, and then proceed to fail within about five minutes because all three of us get knocked unconcious.

The portals around the room. When you walk into one you will be spit out in the opposite one in the room. Thus if you walk into one of the ones at the end of the room you will come out at the other end. The trick I used was to go into the portal, come out on the other side of the room, blast the collector as he comes across at me, walk through, revive my teammates, rinse and repeat.

Yeah, I think where I was going wrong was not trying to revive Ray and Egon until both of them were down. Keeping at least one of them up the whole time kept the Collector distracted long enough to pop a couple shots, and then revive the other. I ended up beating him about a half hour after writing the post.