As a companion piece to the complexity and seriousness of (Total Theatre Award Shortlisted) The Eradication of Schizophrenia in Western Lapland, Ridiculusmus premiere this low key, high comedy two hander loosely framed around the archly metatheatrical concept of putting on a show. This durational art piece is (obviously) about a plague of mice whose main requirement is that everyone dresses in low-rent human-size mouse costumes – useful for a production whose many dubious characters are to be played by a cast of two. But where does the comic sub-story end and the actual show begin? Here lies the rub and it’s a most satisfying friction.

Satirising everything about where we are and what we’re doing (as an audience, as an industry, as the world), the show is unremittingly arch and consistently hilarious. At the same time as hitting its every mark, the material works as foil for the exploration of humans as vermin, the dehumanisation of the elderly, and the brutality of pest control.

This is a show that amply demonstrates the remarkable comic gifts and unique theatrical style that David Woods and Jon Haynes have developed together over the past twenty years. It’s very new, still a little underworked, and flags slightly in the final quarter – but it’s still, already, one of the sharpest shows you’ll catch in Edinburgh. It punctures every self-important bubble of the Fringe and offers a brilliant vision of a world when low grade pest control and high art combine in a completely unlikely and totally convincing concatenation. Once I’ve finally stopped laughing, I’m left reflecting that in the light of recent industry announcements, without Ridiculusmus on its books, the Arts Council’s portfolios will be an infinitely less rich place.

Collaborative company KILN, formerly Kindle company from Birmingham, are having a busy Fringe with three shows at Summerhall this festival. A Journey Round My Skull is the newest of these productions, a solo for performer Olivia Winteringham in which she plays a German neurosurgeon discussing the story of her patient. On stage, her consulting room is oddly toned: every surface – the desk top, the couch – is a matt turquoise and littered with tall anglepoise lamps on scarlet cables. We are cast in the role of the patient, addressed as ‘you’ throughout as she first carefully and kindly and then with increasing passion, recounts ‘our’ relationship, framed as a helpful recollection to assist a memory damaged by the illness she is treating.

The performance is highly poised. It’s disconcerting how much being spoken to as a patient encourages you to adopt that posture emotionally – it’s a very effective format that places us entirely in our doctor’s hands. And of course, she soon emerges as a highly unreliable narrator.

The tale is a compelling one of obsession, intimacy and dysfunction. Writer Nick Walker slowly tightens the screws of unease as the storytelling, barely contained, progresses whilst also peppering his script with learning about brain structure and function that belies the hand of the Wellcome Trust in the development of this project. Then the central scene breaks into a new mode. The company have found a powerfully disconcerting reconstruction of the surgery process that forms the heart of the relationship they dramatise. Biaural sound design by Iain Armstrong projected through headphones put on by every audience member brings the experience of brain surgery – undertaken under local anaesthetic – to alarmingly vivid and personal life. Now the auditory hallucinations that are symptoms of the illness, even the contact of scalpel on tissue and the voices in the protagonist’s head, are in our heads and feel completely shared. We become ‘you’, and our brain is in KILN’s hands.

A Journey Round My Skull feels like a small and private show, elegantly polished and very thoughtfully formed. Yet it’s powerfully formed leaving a lingering sense of vulnerability and violation.

Light is hard to watch. Literally – it hurts my eyes; I wonder if I will develop a migraine. The show’s language is extreme and astonishing: the stage is in total darkness and every image, setting and character is developed using its own shard of light, from spotlight to strip light and everything in between. This is a world painted by movement, images glimpsed and framed only as the light beams are moved. It builds innovatively on the company’s highly developed choreographic language by creating a form articulated by a whole new layer of movement – the angle and rhythm, shape and brightness of the lights themselves, interwoven with the bodies on stage.

As three-time shortlisters for a Total Theatre award (for 2013’s Ballad of the Burning Star, Translunar Paradise in 2011, and Odyssey in 2010), Theatre Ad Infinitum show no sign of letting up on their epic experimentation. Light is a science fiction thriller. It is completely cinematographic in scope, set in a dystopian future where an individual’s mind can be hacked like their email today, using embedded technology that transmits via laser-like light from one brain to another. This transparency of thought has allowed for a cerebral totalitarianism to develop, an idea reminiscent of Orwell here conveyed with the visual panache of Kubrick. A cast of five bring the world to life and the detail of vision – right down to UV technology for teeth brushing and hover bike transportation – is comprehensive. The world feels fully realised, though we see it only in flashes, sweeps, and glimpses, and it is all conveyed in wordless physical theatre of incredible nuance and precision.

It is mind-bogglingly ambitious and also presents huge practical challenges, most particularly choreographically in the management of bodies on stage, into and out of light. Technically it’s incredibly complex – the futuristic setting means that every action demands its own swoosh of technology, the effects mixed live by director (and co-artistic director of the company, who has also written the show) George Mann, within a sound track of sinister grandiosity (that would benefit from greater variation). The story unfolds with a sort of compelling inevitability as one man tries to beat the system his parents created: it’s classic sci-fi fare and the shape holds few surprises. What’s more of an issue though, is that some of its narrative action is unclear. The built in requirement of science fiction to establish the rules of its world mean that we are in unfamiliar territory: we flit in and out of characters’ minds, between real and virtual places, past and present. It’s complex storytelling and there are sequences, including, critically, the denouement, where I’m not sure exactly what the detailed mime is conveying.

Theatre Ad Infinitum have developed a narrative that makes sense of the language of light, but not so much the language of wordless physical theatre (the fact that key narrative developments have to be conveyed by surtitle illustrates the problem). This isn’t a comment on the quality of idea or its execution – physically, conceptually, Light offers much to enjoy and its form is highly original. It’s the sheer ambition of the idea that limits its achievement and this, if there must be one, is the best reason to fail.

In a nondescript living room, on stage in a nondescript theatre, Ans and Greg have a problem. Of that much they, and we, can be sure. They had high hopes to present an inspiring theatrical homage to obscure Enlightenment novel Jacques the Fatalist and his Master by Denis Diderot. They feel it is a masterpiece whose explorations of meaning making in story and life, of freedom and of truth, were centuries ahead of their time, wrapped as they are in a postmodern form whose every act of using language to tell its tale pushes it self-consciously further from the essential truths it seeks to express.

The young duo are steeped in Diderot’s ideas. They are both writers themselves (they tell us). They casually drop erudite quotations about the ideas their ‘Denis’ explores. They trip over one another, they bicker, they gradually expound on the problem they are grappling with – it’s their relationship. No, sorry, it’s that to summarise Diderot’s ideas is to subject them to the very principles – of order, of unity – that his prose and philosophy resists. And plus the world has changed a lot since the Enlightenment. It’s harder to believe in anything – the structures Diderot was dismantling perhaps now come ready dismantled. But so long as they keep talking, the problem is deferred. And meanwhile they have some issues between themselves to try and sort out.

Where the World is Going, That’s Where We Are Going won the award for young theatre at Belgian theatre festival Theatre aan Zee, and is presented as part of the Big in Belgium showcase of the best new Flemish work at the Fringe, and the production offers fascinating insight into a different theatre vision. This is performance as conversation, packed with philosophy – a salon of ideas whose careful writing (by sisters performer Ans and dramaturge Louise Van der Eede), inevitably exacts the principles it discusses. We are invited to be mindful, to bring ourselves to the table, and the performers practically invite this too in their style and manner. The show feels immediate, real and inviting, at the same time as being self-consciously scripted and staged. This freshness of tone is necessary because the conversation is circular, miscommunications abound, and the ideas are dense. Its writing is clever, its performers charming, the form quite hard to digest – in short it’s a perfect, difficult candidate for a programme platforming new Flemish theatre to new audiences.

This production is presented in Edinburgh by Theater aan Zee, Richard Jordan Productions, Theatre Royal Plymouth, and Big in Belgium in association with Summerhall

Leeds-based verbatim company The Paper Birds return to the fringe with their fifth show, an examination of the conditions for and experiences of being ‘Broke’. They describe the production as developing, aptly enough, in straitened circumstances, encouraging their return to a model of making work focussed on the company’s core members: director Jemma MacDonnell, performer Kylie Walsh and composer Shane Durrant.

The scene is set on a suitably cramped stage, bunk beds, screens, and boxes are crammed into the Pleasance’s petite Jack Dome. The opening is compelling: at either side of the stage inside two gauzed booths, two women, who are strikingly similar and dressed almost identically, scroll and rewind through a series of interview snippets about experiences of debt. It’s fast and precise, the lighting and effect of the overlaid projection makes me question if what I am watching is live or on film. They seem like the same woman, but then represent a range of voices in performances that are tight and expressive, both vocally and physically. I believe in each character as he or she appears.

From here the show opens out into more familiar devising fare. We are in a child’s bedroom and a story is being told, a story about treats, about money and sweets. The company collage an assortment of interviews and information around this frame, at the same time using language that’s metatheatrical – they portray their own interview processes and their own experiences of money management and running the show. All are underscored live by Durrant, folded into the bottom bunk, and scenes are propped with children’s toys. From time to time we revert to the experience of the story’s teller, a young mother trapped in the frightening grip of debt.

The problem is that the economics of debt, the definitions and causes of poverty are vast and intractable subjects and the company find it necessary to simplify in order to shape and create connections across their material. One way they have achieved this is by giving considerable play to their own experiences around money, but this unsettles the rhythm of the storytelling, and gimmicks like a gameshow scene, though related to the theme, further muddy our relationship to the protagonist where the emotional heart lies. It’s never entirely clear why this character is doubled and it feels like there’s still a stage of editing and refining to go on for the show to fully articulate itself. The company do discover some powerful motifs, such as the recurring horror of a ringing telephone interrupting scenes, and some strong images, such as when the harassed debtor tosses and turns as numbers scroll across her mind and body.

Yet their desire to create a complex weave of character, information and metatheatricality makes this complex subject too slippery to get a grip on. In an age of austerity we are all saturated with media information and stories about debt and I entered Broke hoping for a new perspective. An intriguing thread does emerge across interviews about the ways your attitude toward money is shaped as a child (reflected in the design dramaturgy), but when the defining question about how you might talk to your own child about managing money in the future is asked, the company can only leave it hanging.