The stunts themselves are impressive and, in the case of the glass, difficult to watch, but even as I did I found myself wondering how he did that. Now the best part of the film is the conclusion where Brown plays back a recording of the show that had been shot from the wings. Having just completed his final stunt (which is impressive) he then picks bits from his show where he had dropped in suggestive remarks that I hadn't even picked up on but, hearing them again, you hear him basically saying what is going to happen in his final scene.
Am I totally convinced that no sleight of hand or trickery is involved at any stage of his show? Well, no frankly, but seeing how he does it and getting the "here's how I did it" at the end does make it all the more enjoyable and convincing because it does leave you with very little to say other than agree that he has effectively managed to manipulated the actions of a mass of people just by using the power of suggestion.
Fans will love this but even myself, as a casual viewer and cynic have to admit that it is an enjoyable and mystifying show and that Brown's style and sense of showmanship makes it lively and engaging.