THERE IS a regrettable modern trend towards making audiences wait an inordinately long time for the interval. It's regrettable not because of the strain it can put on bladder and spine (though you do occasionally wonder why directors are so determined to make you suffer for their art), but because of the strain it can put on the play and the actors.

Jude Kelly's King Lear for the West Yorkshire Playhouse, for instance, takes you all the way to the blinding of Gloucester and the death of Cornwall without a pause. You can see the logic: the first half becomes a steady crescendo of madness; by the interval, things have got about as bad as they can get and the second half is a scramble towards the light.

The drawback is that, confronted by such a huge unbroken span of drama, you're all the more acutely aware of the incoherences and blank spots in Kelly's Lear. That probably sounds more damning than it's meant to. This is a strikingly intelligent production, full of powerful ideas and remarkably alive to the nuances of character, but by the end of the evening you feel numbed with intellectual effort rather than pity or terror.

Partly, that's because all Kelly's best ideas are saved for the villains, treated here with an unusual degree of compassion and insight. In the opening scene, for example, when Lear is demanding that his daughters testify their love as the price for a share in the kingdom, Goneril and Regan (Tricia Kelly and Alexandra Gilbreath) aren't nearly as glib as Cordelia makes out. They play the game, but at considerable emotional cost. In particular, Regan's chilly echoes of her sister's sentiments emerge here as the frozen inarticulacy of a child humiliated and abused by her father's cloying affection. Damien Goodwin's Edmund, too, is an intriguing figure - a nihilistic, self-loathing student, whose soliloquy on bastardy is less self-justifying rhetoric than a search for answers.

Kelly has less to say about the goodies, though: Robert Bowman is a perfectly decent Edgar, in both senses, but you never have any real clue as to what makes him tick; while Maria Miles's Cordelia is a cipher, a gormless hippie- chick. And throughout, there's a sense that Kelly is paying too much attention to the details, not enough to the big picture - so while Edmund's early scenes are excellently conceived, the transition from fumbling student to man of action and great lover is glossed over entirely.

It probably seems strange that I haven't said much about Warren Mitchell's Lear; but that's largely because he is an oddly marginal figure. He begins superbly, dancing on at the head of a train of merry followers, soliciting applause for his every remark, a vain, spoiled ruler and a capricious, demanding parent. He is good, too, at the height of his madness, grinning and capering with savage energy. The simplest thing to say about his performance is that he scales the heights all right, but he doesn't reach the depths. That's a little unfair - there are moments of great tenderness: when, for instance, he tears off his clothes ("Off, off you lendings") and stands naked for a moment, he manages to convey not only Lear's new vulnerability, but also the immense power of which we're now seeing the wreck.

There's something reticent about Mitchell's grief, though; it doesn't fill the stage, it doesn't reach out and grab you as it should. This is characteristic of the whole production. With the help of excellent lighting and sound, Kelly sets up an impressively chaotic, gloomy atmosphere; but softer emotions find it hard to pierce the gloom, and by the end you feel that this may be all very sad, but it's not quite tragic.

Ray Cooney appears to be in some danger of garnering, late in his career, a reputation as an accomplished theatrical craftsman. A hard look at Funny Money, his 17th farce, ought to knock that one on the head. The plot revolves around the accidental acquisition of a briefcase full of used pounds 50 notes by a mild-mannered accountant (played by Cooney himself); his efforts to flee the country before the loot's real owners track him down are thwarted by various policemen, friends and his stay-at-home wife.

There's nothing craftsmanlike about this comedy - too often, you feel that the plot has been held together with a bit of rope lashed round here, a handful of nails banged in there. A lot of the action relies on fundamentally implausible reactions (people making up lies they don't need to make up, or going along with them for no apparent reason); and the pacing is very uneven, with long joke-free stretches.

Still, even if it isn't artistic, it's not boring. Cooney gets some excellent support from Lynda Baron and, especially, Henry McGee (the suave one on The Benny Hill Show); and it's a measure of his skill as a writer that he can even make Charlie Drake seem funny, in a running joke about a waiting cab-driver that's straight out of Arsenic and Old Lace. Theatrically, this is the equivalent of an allotment shed - a lot of bits and pieces picked up here and there. It looks flimsy, but it keeps the rain off.

By contrast, Joseph Blatchley's production of Don Juan Comes Back from the War, inaugurating the Gate's brief season of 20th-century Don Juans, is the theatrical equivalent of a pile of rubble in a skip. Odon von Horvth's play - really, a collection of sketches - offers a Juan converted to romantic monogamy by the horrors of the First World War, but finding it hard to keep his ideals in the man-hungry, amoral world to which he is returning. Blatchley gives us the play as it might have been performed by a bunch of women in a post-war wasteland - so that bad acting is the house style. But convincing bad acting is hard to do; here, it just comes across as acting badly, and an excess of howling and wailing drowns any of Horvth's subtler points about sex and death and what myths can survive an apocalypse.

'King Lear': West Yorkshire Playhouse (0113 244 2111) to 28 Oct; 'Funny Money': Playhouse, WC2 (0171 839 4401) to Jan; 'Don Juan Comes Back': Gate, W11 (0171 229 5387) to 21 Oct.