"Truth" is something reviewers are drawn to. It ought to be a familiar concept, but every time it turns up in a show it's still fascinating. None is more fascinating than Hannah Gadsby's truth, the importance of which deafens everything and bears the weight of the ultimate sacrifice of Gadsby's comedy career

Nanette is the announcement of her retirement and the strength of that truth. After more than a decade in a career governed by words, this swan-song is heartbreakingly articulate, and super-sharp in the precision of every step towards a punchline – or the deliberate, in-your-face refusal of a punchline. It feels like artistry.

Gadsby comes from a small town in Tasmania and has an easy direct delivery, as if you've just pulled up a chair and joined her on her front porch. There's a sophistication and intelligence to her ideas that comes across as wisdom. And there's an angry passion that has been told to simmer down, but can no longer do so and should never have been quietened in the first place. It's a visceral anger that demands respect and to be heard, exposed by increments, delicately threaded through all of her material – from Picasso to Bible stories and coming out.

She holds a great balance between intelligence and accessibility. Gadsby's past in Art History comes to the fore here, provoking important questions about how women are represented in art and in history – another tug at a thread pulled to expose muted stories that need to be told. She is imparting learning in that magical way good teachers do; placing questions in minds to kick-start thoughts that challenge the status quo. And she tackles every status quo, every corner that has tried to tell her what to think, from long-time lesbian fans of her comedy to a government that outlawed homosexuality until 1997.

Gadsby describes Nanette as part theatre, and it needs to be considered as such. Not because it is overtly theatrical, but because unlike a pure comedy show, it chooses at times to deliberately build up the tension and not dissipate it. Its main directive is not to make people laugh, although at times it does; its main directive is to make people think, from other perspectives, other experiences. And in this it succeeds dramatically. It's no wonder this particular show has been picking up some of the most respected performance awards on its road to the Edinburgh Fringe.