Six hours of theatre sounds like a lot, but when it's played out on a film-set-cum-stage that you can walk around designed by Ivo van Hove and collaborator Jan Versweyveld, then, trust me, it positively flies by.

There are regular breaks in the action of Roman Tragedies, a mash up of Shakespeare's Coriolanus, Julius Caesar and Antony and Cleopatra; every half hour to an hour the lights come up for a few minutes and you can move seats or get a beer or some food from one of the bars onstage. After the first 30 minutes of the show - the beginning of Coriolanus - it's a theatrical free for all. You can stay in your seat or head for the stage to sit in a sofa or stool right next to, if you're lucky, Brutus or Cassius.

Essentially Roman Tragedies allows the audience to act as the plebeians, sitting in the midst of the rulers as they bicker and battle all around. If you do head from the stalls to the stage, you can watch the plays through live action or on one of the many big TV screens broadcasting what is happening a few yards from where you are.

From this perspective, it is often hard to keep track of the actual plots of the three plays (although most of us will be familiar with Shakespeare's stories). There's no simple thread of narrative made clear to the entirety of the audience. There are myriad viewpoints and angles from which to watch the show and depending on your attention span, you will be listening more in some points than others. What you get from this way of watching is a glorious collection of theatrical and filmic fragments. The show makes each of us a voyeur, watching with a clear view of the action or from TVs or through the leaves of various pot plants. It brilliantly reflects the way in which we hear the stories of our rulers in real life. These are patchy realities, punctuated by sudden sound and fury - it's always hard to catch the whole truth and nothing but.

Roman Tragedies is exquisitely weaved together by director van Hove, whose ability to make magic out of a sprawling, cross-media, immersive show is remarkable. From the makeup department at the edges of the action to the (very few) stage hands delicately managing the audience, this is an intensely theatrical experience. It's also surprisingly fun. The regular breaks mean you can digest what has just happened, get a drink or just stare into space for five minutes if it is all getting too much.

The cast are superb, with Hans Kesting leading the way with a magnificent Marc Antony in Julius Caesar and Antony and Cleopatra and Chris Nietvelt playing a hilarious, unpredictable and fiery Cleopatra. The whole ensemble are taut and convincing. For the final 75 minutes we are directed back to our seats in the auditorium to watch the end of Antony and Cleopatra, complete with real snake, and it is devastatingly good. The show is epic, real and transposes Shakespeare's plays into a thrilling depiction of modern politics in which the audience is placed right at the centre.

Roman Tragedies runs at the Barbican Centre until Sunday. Obsession runs at the Barbican Centre between 19 April and 20 May.