Sam Simmons: Fail, Soho Theatre, London

It's a tricky task that the Australian comedian Sam Simmons has set himself – showing the lighter side of suicide. He's prepared for failure, of course, that's what brought him to the point of despair in the first place.

The back story of this show is easily explained on paper but the neurotic jumble of comic effects Simmons employs to tell it means that the gravity of the premise ultimately becomes featherweight, lost in gimmickry and goofery, much of which appropriately teeters on the pass/fail margin.

The central conceit has the moustachioed clown playing a gameshow against his own mind. Many of the questions are amusing non sequiturs, "In which town was Tony Blair built?" runs one. "Is it wrong to feed your cat a Viennetta?" enquires another. At other times, we get the feeling of a mind turning in on itself, as it reminds him of past indiscretions and embarrassments.

In between questions, Simmons occasionally leaps up and performs a cheesy dance – this might be a loopy variation on the gameshow theme called "carpet or floor?" that sees him skip between the two surfaces. Quite often it feels as if he is merely posturing for easy laughs. "Ball of Wool" and "Little Key, Little Pocket" are ditties that require no more than those lyrics; pretty twee stuff.

A list of loves and hates hangs either side of Simmons throughout like two columns supporting the show's theme. Such lists are a tried-and-tested device from which stand-ups can juice some quick gags and Simmons duly obliges, laying into cabbages as being "Satan's lettuces" and riffing on couples taking over pavements. In between his bêtes noires and the morsels of happiness listed at the end (soap bubbles, breasts and men dressed as a hotdogs are among his salvations), he explains that he has recently suffered a period where his failures made him entertain suicide. The explanation comes midway through the show, almost too late to enable it to hang together. Meanwhile, the pay-off of Simmons's likes list marks the final shift to the tangible from the absurd. While engaging as a whole, the show's texture is flawed, pleasantly floundering with neither narrative nor abstract rhythm to drive it successfully to a coherent destination.

To 30 July; then Edinburgh Fringe Festival with his new show, 'Meanwhile' (www.samsimmons.com.au)