Complex sentence: The subject matter, terrorism and betrayal, was extremely challenging (in the last measure of the piece, a character suicide bombs the audience) but despite the emotional violence of the work it was a major critical and popular success.
Split into simpler sentences: The subject matter, terrorism and betrayal, was controversial, and in the last measure of the piece, a character suicide bombs the audience. Despite the emotional violence of the work it was a major critical and popular success.