The theatre roof is open so if you have bought tickets for the standing area you get wet if it rains. Yesterday London turned on a good old downpour. Thankfully we were seated under cover. The stage projects out into the open so even the actors get wet. They don't let that bother them one jot. For this particular play the stage had slots cut into it either sides. People stood in there with just their heads popping above stage level.
The actors interact with the audience a lot. It's such a small intimate theatre. No fancy dancy lights or amplified sound. Fantastic!
This is definitely on the just do again list.