Shakespeare exists to be refracted and filtered through the age in which he is presented. So there's every good reason for the Donmar's artistic director Josie Rourke to approach the eternally problematic Measure for Measure as a twice-told tale that effects a startling shift in time period and gender politics at the interval.

What better way to celebrate a homecoming than with a party? That is the capacious-hearted thinking behind this new musical version of Twelfth Night, which additionally marks Kwame Kwei-Armah's debut production at the helm of that undeniable dynamo otherwise known as the Young Vic.

You always wonder about those final scenes of Shakespeare’s tragedies. Are they really needed dramatically; do they work? We understand, of course, that a closing exhalation may add impact to high passions just witnessed.

“Well, that was really sweet,” one young audience member in front of me remarked on his way out of Edinburgh’s Lyceum Theatre. And yes, there’s no denying that director Wils Wilson’s colourful, psychedelic, summer-of-love-set Twelfth Night, the Lyceum’s season opener in a co-production with the Bristol Old Vic, is warm and generous, lovingly crafted, and – yes, touchingly sweet.

Henry V is a play shot through with martial energy and the terrible chaos of war. The almost overpowering violence and energy that characterise the story give the unfolding of the drama a permanently disrupted form, as if the unpredictability of history and the reality of bloodthirsty men going berserk on the field of battle had undermined Shakespeare’s usual formal strengths.

If ever there was a play of “well bandied” words, it’s surely Love’s Labour’s Lost. The early Shakespearean comedy may once have hit a highpoint for verbal wit, but much of that context – the word play, the allusions, the sheer stylistic preening that must have had a certain in-joke quality for its initial courtly audience – has rather evaporated over the centuries.

A break-dancing mini Michael Jackson, a transvestite Neptune, and a hero who wears his hubris as proudly as his gold-tipped trainers, are unconventional even by Shakespeare’s standards, but they all play a key part in this joyful act of subversion.

It feels like Michelle Terry’s first summer season at the Globe has been building up to Emilia for a while now. The theme is Shakespeare and race, so Othello was something of a given. It's joined by The Winter’s Tale, as if the Emilias of these two plays have been waiting for their chance to step into the spotlight.

Jonathan Munby's production starring Ian McKellen, first seen last year in Chichester and now transferred to the West End, reflects our everyday anxieties, emphasising in the world of a Trump presidency, the dangers of childish, petulant authoritarianism. And while King James I was keen to promulgate the benefits of a united kingdom - having joined England and Scotland under his rule only three years before Shakespeare's tragedy was presented at court in 1606 - the corrosive nature of divisions within the state is equally clear now in the era of Brexit. The Union Flag features frequently in Paul Wills' design.

Munby is an inspiring director, especially of Shakespeare, mining text and motivation with meticulous care. His Globe productions of Antony and Cleopatra and The Merchant of Venice were especially revealing. Here, in a modern-dress setting, he makes much of the pagan nature of Lear as well as contemporary concerns. This places the action - clear and fast-paced though it is - in a strange world where people in combat gear pay deference to "the gods", showing respect for Apollo with ritualised hand gestures. 

If there are more ideas than the production's frame can easily contain, at its heart is Ian McKellen's mesmerising performance, exploring the vulnerability of old age, the absoluteness of death, the fragility of life and of sanity with such humanity, such a mixture of twinkling mischief, unforgivable cruelty, gentleness and sad acceptance of his failings that it takes your breath away. Much was made last year of the importance of the intimacy of the Minerva Theatre, which seats fewer than 300 people, but McKellen's performance remains unforced, even conversational, in its new surroundings. This is aided by the design, which includes a central walkway through the audience and a panelled wooden curve often limiting the stage area.

To begin with, Lear appears alone for a moment, enjoying the stage-managed surprise he is about to spring. His daughters sweep in dressed in ball gowns and the court sing together. All seems well-ordered, even good-natured, until the fateful fracturing of the kingdom. Sinéad Cusack plays good-hearted Kent, banished for speaking up and soon disguised as an Irish-accented male servant to the king in his homeless wanderings. The gender change makes perfect sense (as a similar casting, of Saskia Reeves did in Nancy Meckler's Globe production last year) and Cusack carries it off brilliantly.

Of the daughters, Anita-Joy Uwajeh as a strong-minded Cordelia and Claire Price as a Sloaney, pearls-and-headscarf, Goneril are new to the cast. Kirsty Bushell's fascinating Regan is unstable, kittenish, manipulative, sexually excited by the blinding of Gloucester. This is especially horrific, carried out with a meat hook in an abattoir. The heads of the dumb beasts - cow and pig - have already witnessed Lear's mock arraignment of his daughters.Lloyd Hutchinson's Irish Fool (above with Sinéad Cusack as Kent) plays the banjo and cheekily mimics his master - rather well. His witnessing of Gloucester's blinding and subsequent encounter with a murderous Edmund seem odd additions, however.

Danny Webb's Gloucester is a fine foil for McKellen and their Dover scene very moving as two old men, in the wisdom and foolishness of age, learn the error of their ways while facing mortality, one blind, the other madly wielding a bunch of weeds like a gun. Luke Thompson visibly grows up as Edgar and James Corrigan makes a clever, sardonic Edmund. But, however good the rest of the cast, it is McKellen who is unforgettable. His career has encompassed many of Shakespeare's major roles, including Edgar, Kent and, in Trevor Nunn's operatic 2007 RSC production, an earlier Lear. If, at 78, this really is his last stage performance in Shakespeare, it makes a stunning finale.

• King Lear at Duke of York's Theatre to 3 November 
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@heathermneill

Overleaf: more great Lears

It's been raining in Regent's Park. On a balmy summer evening during a prolonged dry spell – perfect for outdoor theatrics – it seems ironic to tempt fate by creating artificial downpours and thunderstorms.