Visual Arts: Michael Kane,Drawings and sculpture. Rubicon Gallery, 10 St Stephen's Green, Tues-Sat noon-6pm. Until Apr 14. 01-6708055 UnstrungCecily Brennan. Taylor Galleries, 16 Kildare Street, Mon-Fri 10am-5.30pm, Sat 11am-3pm. Until Mar 24. 01-6766055

Michael Kane's introduction to his exhibition of drawings and sculpture at the Rubicon Gallery begins on a downbeat note. He set out, he writes, to produce "a coherent set of images evoking the story of Orpheus and his love for Eurydice". But "plain continuity was hard to sustain in the face of so little information still remaining about the original tale". Surely this is an odd way of looking at the project.

Apparently, the kernel of the myth of Orpheus and Eurydice, the story of a bereaved protagonist who descends into the underworld to recover the person he has lost, turns up in the folklore of many countries. A large number of writers and artists, notably including Ovid in the Metamorphosesand Gluck in his archetypal opera Orfeo ed Eurydice, have fashioned thoroughly satisfactory narratives from this basic template.

It's perfectly legitimate to take an existing myth and inventively rework it for your own time. In fact, it's something that Kane has himself done in the past with considerable success, and it's what he proceeds to do in this case. So the difficulties he outlines at the outset seem non-existent. Perhaps his doubts have to do with the particular bodies of work he has produced - a group of bronze sculptures and a sequence of drawings. They are thematic and episodic, and sometimes vaguely relevant, rather than "a coherent set of images" telling a sequential tale.

All of which is perfectly acceptable, except that one longs for a bit more - more focus, more dramatic shaping - precisely because there's something really promising in what he offers. His foray into sculpture is a departure. Although the pieces are cast in bronze, their beginnings are not exactly orthodox. In fact, they look as if Kane knocked them together from bits of cardboard packaging and other prefabricated containers, joined with strips of masking tape. It's an interesting approach, and the rough-hewn quality is effective some of the time.

The best are several blocky heads and a half-figure that has a Beckettian quality. Full figures are less convincing and least convincing of all are a car and a van. The idiom has parallels with Matthew Monahan's virtuoso, disjointed figure sculptures at the Douglas Hyde (definitely worth seeing before the show closes this Saturday), but alas by comparison Kane is half-hearted in his approach.

He fares a lot better in his drawings, which are characterised by dread, a brooding darkness, sexuality and the threat of violence.

All of this is more than licensed by the source. Eurydice was killed by a snakebite when she was fleeing an attempted rape by Aristaeus.

Having lost her a second time, and on the point of winning her back, Orpheus, by some accounts, was instilled with a hatred of all women and was consequently, if unluckily, torn apart by the Maenads. His head, ironically, given his antipathy, floated down the Hebrus and came to rest on the Island of Lesbos. Not a barrel of laughs.

Kane transposes the situations and feelings to equivalents in contemporary, night-time Dublin, conjuring up a realm of dark streets and perhaps darker passions. The fact is that his work has always viewed romantic and sexual relationships as fraught and dangerous, with intense hatreds lying just beneath the surface of love, and a profound distrust between men and women. His depictions of figures possessed by desire have a raw, driven eroticism in keeping with the mood of heightened drama. Orpheus may yet yield more material for him.

THE CENTERPIECE of Cecily Brennan's Unstrungat the Taylor Galleries is a film installation of the same title. To some extent this brief work depends on the element of surprise, so it would be unfair to detail the nature of the ordeal that engulfs the hapless androgynous subject. It seems fair to say, though, that the piece is straightforwardly symbolic of endurance in the face of unforeseen, uncontrollable pressures and events.

There is an element of theatricality to the stark mise en scène and, with the inky black-and-white 16mm cinematography, it recalls aspects of silent comedy and Beckett or, to put it another way, Film, a collaborative project involving Beckett and Buster Keaton, and one that underlines the proximity of existential tragedy to slapstick.

Humour is integral to Beckett's bleak world. It's not so much that he leavens the mix with a bit of a laugh, more that the human predicament incorporates a comedic aspect, albeit a terrible and not especially comforting species of comedy. The upside for Beckett the writer and dramatist is that humour rescues his works from coming across as being unduly earnest or po-faced. It feels as if Brennan, who comes to narrative performance from a background in still images and objects, that is in drawings, paintings and sculptures, has not yet figured out a way to second-guess audience reactions as Beckett did early on. We have just the bare, direct statement.

One of her two short video pieces, Collapsing Can, is perhaps more ambivalent about allowing humour into the equation. It's a Fischli and Weiss moment, recalling their amazing, and incidentally very funny The Way Things Go, and as the title implies it consists of a tin can imploding under the force of unseen pressure and toppling off its platform. As with Unstrung, it uses the language of slapstick, but with a different intent. In the remaining video work, Balancing, a hand reaches out, gently and tentatively, to a wall for support.

If there are references to slapstick, what replaces the punchline? It is as if Brennan is aiming for an air of scientific dispassion, aspiring to be a disinterested experimental observer of her subjects. The watercolours, understated and persuasive, with several really memorable images among them, are figure studies. They fall into two categories. In one, the subject is lying prone, blankly unfeeling, as though imagining death; in the other, clenched up or with hand held over face, suffering some sort of torment. While there is nothing indulgent or sentimental about her view of this troubled being, it is as if the work, in still and moving form, does need one other layer or dimension, perhaps something that works against its prevailing idea.