Theatre presented in the round (ie, with the audience encircling the stage, which often has few or no vertical backdrops) is an ingenious way of making those watching a play feel part of the proceedings, or at least closer to them. The "us and them" barrier is removed by having the performance take place just feet (sometimes inches!) away from the audience. You can see the actors' faces clearer, the expressions they make, often even the thoughts running through their minds. It can be a beautifully immersive device to make the experience more memorable to the viewer, and more exhilarating for the performer.
But one drawback of staging in the round is that at some point the performers will have their back to one section of the audience, meaning projection is key to maintaining that shared space relationship. The most common way of tackling this is to have the performers move regularly around the space, changing direction and perspective so as to keep as many plates spinning as possible.
