Julius Caesar, Coliseum, London Siegfried/Götterdämmerung, Royal Opera House, London

Bloody and bold, choreographer Michael Keegan-Dolan's English National Opera production of Handel's Julius Caesar proposes a parallel between big-game hunting and seduction. It's a man's world, this plywood Alexandria: a place where severed heads roll like bowling balls, where a Roman emperor can swagger about in cowboy boots, boxer shorts and a prideful grin, where eviscerated crocodiles are strung from the ceiling, where women in gimp-masks ape caged panthers. It's a man's world, all right, an Ernest Hemingway safari laced with jiggles and wiggles from a dance troupe and buckets and buckets of gore. But what a miserable shower these men are. Tolomeo (Tim Mead) is a psychopath. Caesar (Lawrence Zazzo) is a chump. And Sesto (Daniela Mack) is a girl.

In Keegan-Dolan's reading, Sesto undergoes gender-reassignment, becoming Cornelia's daughter. Instead of a love story between a military hero and a manipulative queen, Julius Caesar is played as a girl-power revenge tragedy. Anna Christy's dainty Cleopatra is no vamp, and Patricia Bardon's tigress Cornelia becomes the focal point, resisting the brutish advances of Andrew Craig Brown's Achilla and the baroque humiliations meted out to her by Tolomeo with a croquet mallet and a giraffe's tongue. (Don't ask.)

Though some of the choreography is eloquent and pointful – gestures of yearning that echo the curve of Janice Graham's obbligato violin solo, a frenzied flutter of vultures' wings in Cleopatra's lament – as much again is fey and rhythmically disruptive. Christian Curnyn conducts a swift, stylish account of the score, with excellent work from the bassoon, horns and theorbo. There are no ensemble problems between stage and pit – Andrew Lieberman's set designs bounce the voices forward. Blowsy cadenzas aside, Zazzo sings with a virile, ringing tone. Mead excels, while James Laing sounds sweet and true in the tiny role of Nireno. Christy's phrasing is meticulous, but it is Mack and Bardon who are allowed to develop real authority in an otherwise undernourished, undernourishing, counter-intuitive production.

In the third and fourth music-dramas of the Royal Opera House's first cycle of Der Ring des Nibelungen, conductor Antonio Pappano digs deeper and harder into Wagner's spiralling chromatic opiates. Book upon book is lifted, read and discarded in Keith Warner's production – thrown angrily away by Wotan in Siegfried, held as a talisman in Götterdämmerung – but the knowledge runs out. Here we see the progressive curdling of Mime's temperament (those nagging waltz rhythms), the sentimental education of Siegfried, the dreadful legacy left to Hagen, the betrayal of Brünnhilde, and the collapse of a world order built on stolen gold and gross exploitation.

Heavy-shouldered and shaven-headed, with a voice to match, Stefan Vinke was unafraid to play Siegfried as a thug and a fool, a bumptious beefy lamb to the slaughter. Gerhard Siegel's Mime was beautifully judged. Bryn Terfel's long-awaited Wanderer/Wotan did not disappoint, all growl and glow and bitter weariness, while Susan Bullock navigated Brünnhilde's journey from ecstasy to desolation, fury and redemption with bravery and intelligence. Among the smaller roles, Sophie Bevan's blithe Woodbird, Karen Cargill's richly focused Second Norn and Rachel Willis-Sorensen's flighty Gutrune stood out for expressivity and ease. Stricken with bronchitis, Wolfgang Koch mimed the role of Alberich in Siegfried (Jochen Schmeckenbecker drafted in from Vienna to sing from the side of the stage), recovering to powerful effect in Monday's Götterdämmerung, where his cough and rasp became integral to the character. John Tomlinson's watchful, tarry-voiced Hagen was, for me, the most powerful performance in the Cycle.

Some frustrations remain: why does Maria Radner's Erda appear on a leather-skirted umpire's chair, disappear while Wotan is addressing her, return on foot to deliver her side of the story, disappear again when he resumes singing, then return once more on the chair? And who are the young people who press against the New Money plate-glass walls of the Gibichung palace and strip to their vests as Brünnhilde combusts? As with coughs, snores or rustling sweet-wrappers, you have to ignore these and concentrate. For all the clunk-click of carabiners and ladders, the rutting of fibreglass antlers against tiled ceilings, something magical happened. And the loudest applause should be for the 114 instrumentalists who stood with their conductor in the bed of the Rhine at the curtain call, and will be playing it all over again today.

Ring cycle to 4 Nov (020-7304 4000) and broadcast live on Radio 3 on 16, 18, 21 and 24 Oct. 'Julius Caesar' to 2 Nov (020-7845 9300)

Critic's choice

Smith Square Autumn Festival starts on Wed, with lunchtime, evening and late- night performances of Brahms, Glass, Elgar, Monteverdi, Jonathan Harvey and John Cage by Songsmiths, Anemoi Ensemble, The Smith Quartet, La Nuova Musica, Rolf Hind and Group 627 at St John's, Smith Square, London.