Tracy Letts begins his trailer-trash comedy Killer Joe with the corniest of platitudes. A runaway druggie named Chris Smith needs $6,000 to stop ‘some guys’ from killing him. He asks his dad who declares himself skint but together they plot to bump off Mrs Smith, Chris’s mum, and collect her life insurance. Interesting idea. Luckily there’s a hitman available who works as a cop and goes by the sobriquet, ‘Killer Joe’. (Note to police forces everywhere: an officer whose nickname suggests a second career as an assassin may be worth investigating.) Joe wants payment up front and the penniless conspirators offer him Chris’s attractive sister, Dottie, as a ‘forward loan’.

Joe seduces the nervy young sexpot over a tuna supper and the creepiness of the set-up is diminished by his swaggering eroticism and by Dottie’s eagerness to lose her virginity. Legally, Joe is a rapist but he’s also chivalrous, sensitive and decent. Having ensnared Dottie, he moves in with her and loses interest in murdering Mrs Smith who is now, to complicate matters, the mother of his girlfriend. The killing goes ahead anyway and the consequences are macabre and comic. The life insurance ends up in the wrong hands and several more unexpected twists follow as Joe finds himself in control of the Smith family who are unable to pay him the cash they owe. But this amusing and intricate web starts to get too tangled and, as the play reaches its conclusion, a swift escape route is needed. Easiest solution? A bloodbath. The writer hits the ketchup button, and passes a loaded gun to the least violent character, who starts to shoot everyone in the trailer. Then, a final unexpected twist. This is the least satisfactory part of the show but it doesn’t matter. It’s over.

The production works extremely well as a gripping piece of comic-horror nonsense. It’s notable that the script lacks any ethical dimension. Every character, including the bashful young Dottie, knows that Mrs Smith is on a death list but no one tries to warn her, or to forestall her execution. The assumption here is that trailer folk are devoid of morality, and this gives the show a powerful whiff of ‘safari park’ condescension. Audiences can gawp from a safe distance as the wild animals tear each other apart.

Nudity is an important pull factor too. Neve McIntosh (Sharla) enters the stage with all her bits and bobs on display. Sophie Cookson (Dottie) disrobes completely while under orders from Joe (Orlando Bloom). He too obliges the peeping toms by flashing his unclothed rear extension at the start of the second half. But Bloom’s moon appears in the skies for a maximum of five seconds before suddenly vanishing. Lorgnettes in position, please, oglers. Why am I reporting on the thesps’ nudity rather than their artistry? Their choice, really. Had they kept their togs on I’d have been compelled to assess their other talents. Let me add that Orlando Bloom, often a handsome void on screen, is excellent in this tricky, ambiguous role. His sinuous athleticism dominates the stage and he plays Joe as a watchful, oily, manipulative sex pest with a curious sense of nobility. Why accept the part? I suspect that Bloom is keeping a close eye on Hugh Grant and has noted Grant’s masterful transition from sugary heart-throb to interesting villain.

Peter Pan at Regent’s Park locates the action in a first world war field hospital. Wendy is a mumsy nurse and the Lost Boys are wounded soldiers. As Wendy, Cora Kirk’s honeyed patience is the show’s best asset. The acrobatics work brilliantly. Peter Pan, dangling from semi-visible pulleys, soars into the air and whirls out across the audience. Some of the secondary roles are performed by over-shouty actors who aren’t easy to like. Sam Angell plays Peter as a brash, cocky grown-up who claims to hail from Kensington but has a Glaswegian accent and sounds like a Govan shop steward demanding longer tea breaks. Tinker Bell is represented by a puppet made from a broken storm lamp.

It’s odd that puppeteers aren’t aware that their illusions fail when the operators are larger than the marionette. In War Horse, the animal convinces us because the huge beast conceals two of its three puppeteers, and the third operator blends in visually because he functions as the groom. Simplicity lies at the heart of the imposture. Here we have surreal eccentricity: the puppeteers are using a light bulb, a translucent shade and a fuel cylinder to replicate a fairy. Was that likely to fool anyone? My son, aged 11, pronounced the show a triumph but his attention was less than fully absorbed. He bombarded me with so many questions that a reviewer behind us hissed ‘shut up’ at him. His custom is to disregard orders from the Critics’ Circle. This time he made an exception.