It's very hard for the films in The Lloyds Bank Channel Four Film Challenge not to look slight, wedged in between the schedules' big boys. That unwieldy title, almost as long as the slot they occupy, does them no favours either, effectively advertising the fact that a certain amount of charitable forbearance is expected from viewers. Add to that the natural addiction of young writers and directors to the melodramatic (out of the six films, only one - the only documentary - did not involve death or bereavement) and you have stacked the odds fairly heavily against these miniatures making any real impact.

Last night's concluding film, Cold Season by Tim Weaver, had been even more unlucky, given that its account of bullying and graveyard chats with the recently departed followed hard on the heels of King Girl, a BBC drama in which the same elements were explored at much greater length. In this, it neatly demonstrated why at least part of the audience's allowances should have nothing to do with the youth of those involved, and everything to do with the intractable nature of these shards of airtime: a 15-minute slot which would probably defeat even the most experienced film-maker. What is the best course - to deliver a fragment which implies a larger work (which seemed to be the approach Cold Season had taken), or to compress a much longer film into the available space? It hardly matters which you choose, because the results are likely to be equally unsatisfactory either way - a sense of skimpiness or a vague lack of resolution.

Which doesn't mean that talent can't find its way through. Of the six films in the series, Bantams was probably the sharpest, a giddy little exercise in vertigo which had found a narrative way of accounting for its brevity. As Daisy dangles helplessly from a stadium roof, held by his mate Karl, their dizzying predicament is intercut with little vignettes of hopeless teenage life - hanging round petrol stations, bunking off school, escaping from rival football fans. I doubt whether imminent death would have provoked Daisy into quite such a philosophical mood as he displays here, but Daniel Caffrey's direction was better than adept (tricky technical problems were elegantly resolved), and somebody deserves large credit for the resistance of temptation (an under-rated component of creative talent). You expected the film to end with Daisy's fall, an obvious occasion for some self-advertising visual thrills. Instead, it left you with a distant, formal framing of a tiny figure dangling over the void - an image which had a much larger resonance than mere cinematic peril.

I also liked Oi Referee!, a neat little film about Sunday league refs which was written by Paul Whittington (exactly how you "write" a commentary- less documentary I'm still not sure). Stuart Everett, the director, had included an interesting stuttering visual style for the referees' view of the action (which seemed to indicate that, if not exactly blind, they might sensibly consult an optician), and you could see that, with a bit more time, the seemingly parochial subject matter provided an oblique angle on much larger issues - on matters of discipline and authority, as well as the national passion for football.

"The Stone Diaries", a film for BBC2's The Works series about landscape sculptor Andy Goldsworthy, reminded you that films can be too long. At 20 minutes, within a protective structure (the old Late Show for example), this would have been perfect, but at 30 minutes it was left flagging a bit. The local sheepfarmers thought Goldsworthy's project - to repair drystone sheep pens - was a waste of money. I don't, given that it looks beautiful, employs local craftsmen and also mysteriously adjusts an ancient landscape (his repaired sheep folds enclose huge boulders). Tim Neil's film captured the craft, and the comedy, of sceptical local farmers turning into involuntary art critics ("It don't look right, not to my eye," said one, questioning the quality of the walling), but it never quite overcame the essential repetitiveness of the artwork in question.