Riggan Thomson (Michael Keaton) is a somewhat washed up former Hollywood star, most widely known for a trilogy of superhero flicks about the titular Birdman. In a bid to garner some respectability and reignite his acting career, he is writing, directing and starring in a theatrical adaptation of Raymond Carver's novel What We Talk About When We Talk About Love.

Acting, quite intentionally, as something of a comeback vehicle for the somewhat washed up former Hollywood star, most widely known for playing Batman in Tim Burton's comic book films, a large part of Birdman rests on Michael Keaton's shoulders.

Keaton is solid in the lead role, creating an escalating sense of Riggan falling out of control with - not only his play - but his life, that, as far as he's concerned, has been going off of the rails since he aspired to being more than just a superhero. However, as is made clear in two bar-room scenes; one with Ed Norton's Method actor Mike Shiner and another with a theatre critic (Lindsay Duncan), perhaps Riggan's creative pursuits aren't driven by a genuine artistic impulse.

Furthermore, he's complicated his backstage life by hiring his daughter (Emma Stone) as his assistant, whilst she's still dealing with having recently been let out of rehab, and by casting his current lover (Andrea Riseborough) in a supporting role.

Whilst Riseborough's character is largely sidelined by the narrative, Stone has some clunky scenes in which she has to give a lumbering diatribe about Riggan's failings to his face. It's her more intimate moments with Norton that show a more interesting and complicated relationship, one that seems to merely set-up one of the film's comedic highlights when Riggan steps out for a cigarette.

In fact, it's primarily thanks to Norton that the film really has any energy, he gives a jolt of fizzy, antagonistic life to the scenes he's in and draws out the best from his co-stars whenever they're sharing the screen.

When we're left with Riggan things quickly become repetititve, in a way echoing a problem that Norton's character picks up on from Riggan's play; that the dialogue says the same thing over and over again, adding nothing new. As the film continues it becomes increasingly guilty of doing this, with numerous potential endings, and whilst it's not a chore to watch the story continue the film lacks any emotional resonance with the characters being interesting but largely unappealing.

Maybe it's a side-effect of the shooting style, with director of photography Emmanuel Lubezki and director Alejandro G. Iñárritu attempting to let events unfurl in one continuous shot (a somewhat cleverly edited series of takes, stitched together). At times this approach does bring the film a fittingly theatrical energy and verve that brings its cast to life, but at other times it causes the film to drag its heels and it sorely lacks the snap that a few cuts here and there could bring to some moments. Worse, the "wizardry" gets in the way and occasonailly pulls the viewer out of proceedings, with the gimmiick becoming just that and not really complimenting the intention of the narrative.

Ironically the film has a sudden imaginative giddy rush in one sequence where Riggan's inner-monologue (an hallucination of his Birdman alter-ego) deluding him into blockbusting fireworks, with a gigantic mecha-bird clawing at a townhouse whilst Birdman stares straight out at the audience growling that this is what we want. And, yes, in a way, it is. Whilst I'm not pining for Michael Bay-isms in a rich, weighty character piece, it's the sense of creativity that this sequence suddenly encompasses, followed by the film's one genuine emotional moment as Riggan stands on a ledge and is approached by a stranger.

There is plenty to enjoy in Birdman, but it's merely the fun of seeing good actors given a chance to rile each other up, to play, but there's something missing from the mix, some sense of purpose or meaning beyond allowing us to give Michael Keaton the comeback he perhaps desires, much in the same way that Riggan wants one.