Antipodean retro-geek comic, John Robertson, wooed and wowed last year’s Fringe with his steam-punk majik mystery tour of 1980’s kilobites kitsch.

Premised on his retro-respect for text-based computer adventure games, this show was a gloriously anarchic blend of audience participation and ritualised humiliation – of the most generous kind. Adhering to the maxim that if it works/don’t fix it/just tweak it a little and re-mix it, he is back again.

He invited, he beguiled, nay he taunted us to dare take up the challenge and visit his Dark Room magisterium of digital delights with promissory rewards of rather pathetic part- inflated Poundland plastic dolphins. The die was cast –  the game commenced and in to the Dark Room of multi-choice the Mephistopheles of mayhem, the Game Master of glitch led pitiful volunteer punters to their nemesis: as long as they assumed the fearless character of – Darren. And that is about it.

Punters are faced with increasingly ludicrous and impossibly paradoxical choices as they witlessly attempt to navigate themselves around The Dark Room. Robertson conducts the proceeding with an X Box controller attached to his chest with two coat hangers – his face under-lit by a torch like kids used to do when telling ghost stories on camp. Quite why he was wearing a rather fetching full-metal corset was never adequately addressed. The mantric repletion of  ‘You awake to find your self in a dark room,’ with the lose-lose non-option of not being able to switch on the light because you can’t see the light switch because you are – yes, in a dark room so you can’t see it – put Robertson’s life in near mortal peril.

His near  nemesis came in the guise of the delightful Melanie – aka an honorary Darren, who caused the Game to crash and  left Mr. Diablo scrabbling to re-boot from the default Windows screen. You had to admire his chutzpa even if it was a set-up. Tuh! Windows indeed. Melanie was dubbed the Windows Witch and given a dolphin as an appeasement to mitigate her spell-craft. By now, you will be beginning to get the general drift of the show. Undoubtedly, Robertson is a crafty master of his unique, niche giddy ephemera. Articulate, perceptive and inventively snappy, exploiting spontaneous moment of comic intervention, he embraces the audience dynamic, targets willing ‘victims’ and has them howling for more.

Not just a glorious excess of gladiatorial venality, boozy bonhomie and sometimes blunderbuss blunt banter – there lies within  – an ingenious method in its madness.

Underbelly, Cowgate. Venue 61. 20.40 1hr. £10.50 (£9.50)