
There is dramatic irony [dramatic irony: An occasion where the audience knows more than the characters do. ]. For instance, the audience knows how wrong Mr Birling is when he makes confident predictions about there not being a war and is excited about the sailing of The Titanic: famously, the ship sank on her maiden voyage. This puts the audience at an advantage over the characters and makes us more involved.

The Birlings' Living Room
There is a lot of tension [tension: A feeling of potential conflict between a group of people. In an audience or reader, a sense of potential conflict, or a feeling of anxiety due to what may be about to happen. ] as each member of the family is found to have played a part in Eva's death. New pieces of information contribute to the story being constructed. The audience is interested in how each character reacts to the revelations.