If ever there was a play which adhered to the dictum “show not tell”, it is Amadeus, the story of the patron saint of mediocrities, Antonio Salieri, and his battle with God over the unjust distribution of talent he sees incarnate in the figure of Wolfgang Amadeus Mozart. Where other worthy plays about geniuses can only tell us about the wonder ensconced in their subject’s brains, Peter Shaffer’s 1979 barnstormer simply stands back and lets the music do the talking. And what music – in the new National Theatre production we are pummelled with masterpiece after masterpiece, a Greatest Hits of Mozart’s work sublimely delivered by the Southbank Sinfonia and so timelessly gorgeous as to justify the price of admission on its own.

Does the rest of the play equal it? That’s a question that bothered me through most of what is undeniably a spectacular evening. Director Michael Longhurst has done several interesting things with this classic, most notably creating something far more exotically theatrical than the text might suggest: this version of classical music’s most famous whodunit (or did-he-do-it?) has no qualms about taking place in the faulty chambers of Salieri’s memory.

Mozart dances wildly on top of his piano while conducting, the orchestra wanders around the stage while playing, time periods are smashed together by thumping bass and Krispy Kreme donuts. Salieri’s opening invocation to “ghosts of the future” is taken seriously, as the creatures of the theatre swell around him and retreat forward and backward as if he is haunted by the entire edifice of opera itself as well as the revenge of the Almighty.

This creates certain undeniable problems: a chorus engaged in a 21st century rave to a remixed Symphony no.25 runs perilously close to adding little while trying too hard. At other times it reaps scintillating rewards: at the play’s turning point the entire set seems to advance on a prostrate Salieri as the Mass in C minor rises in crescendo, one of the finest unities of sound, visuals and plotting I have ever seen in a play.

And then there is Mozart himself. The character as written by Shaffer is an unbearable man-child, I realise – but there is surely a limit to how much an audience can take. Adam Gillen’s rendition takes every last syllable and spits it through a mangle so piercingly boorish that by the end you would be forgiven for thinking Salieri more a fumigator than an avenger. This, it is true, fits with the idea that we are seeing through Salieri’s memory, not the real Mozart but the “Creature” of his nightmares. But that doesn’t make it any less agonising to share a theatre with, and there are some good lines Gillen is losing in the process.

Although, how many good lines? The problem I have – come to think of it – is that for all the brilliance of his central idea, Shaffer was not a good playwright on a smaller scale. The script is frequently odd and jarring, the dialogue not keeping up with the theme, and seeing bit parts like Tom Edden’s Emperor Joseph II played so broadly hardly helps matters.

It is lucky that the night belongs to the towering central performance of Lucian Msamati as Salieri. His effortless portrayal of the self-loathing and caged, helpless fury of this man cursed with enough talent to understand his talentlessness is awesome to behold. Cool and witty, with pitch-perfect comic timing in a character that has no right to be so funny, he draws us in and implicates us all in his jealousy. He is cursed to be the greatest critic of all time, the man who first recognised Mozart’s genius, when all the time he wished to be on stage. In such a thrillingly ambitious and sensually rich production that can bring an audience to its feet, those nevertheless left a little underwhelmed may take pause.

Amadeus is playing at the National Theatre with performances currently on sale until February 1. There will be an NT Live broadcast to cinemas on February 2.

Photo: Marc Brenner