Machete, Venice Film Festival

Machete has its origins in a "fake" trailer Robert Rodriguez dreamed up when he was working with Quentin Tarantino on their B-movie tribute, Grindhouse. It's a full-length film that plays like dozens of trailers loosely cut together. Blood-spurting set-piece follows blood-spurting set-piece with little in the way of characterisation or narrative to get in the way. Rodriguez and his cast – which includes (among others) Jessica Alba, Lindsay Lohan, Don Johnson, Cheech Marin and Robert De Niro – clearly had a blast making the film. In patches, it is entertaining and ingenious. However, the director seems fatally uncertain whether he is making a full-blown action movie or a spoof.

The formidably ugly Danny Trejo plays the hero, Machete. His acting style is from the Charles Bronson school of deadpan minimalism. His character here is an ex-Federal agent, out for revenge against drug baron Torrez (the ageing and still wooden action star Steven Seagal). There are fitful hints that Rodriguez wants to make some polemical points about the racist treatment of Mexicans by American politicians and border guards and about the drug wars that blight Mexican society. Machete is an X-rated version of the Pancho Villa-like folk hero, out to avenge the indignities wrought on migrant workers. De Niro hams it up in enjoyable fashion as a right-wing Texas senator who advocates building an electric fence to keep illegal Mexican immigrants out of the US. Any political subtext is strictly secondary, though, to the many lurid action sequences.

Given the extreme amount of death and violence in the film, Machete is incongruously cheerful fare. You have to admire the hero's ingenuity. While the machete is his weapon of choice, he is adaptable enough to skewer, decapitate and generally mangle his antagonists with whatever other instruments may be to hand. Every time Rodriguez shows us any kind of sharp object in the corner of the frame, we know that Machete will soon find some way of using it for maximum destructive effect. In one splendid scene, he uses the intestines of one of his victims as a makeshift ladder with which to make his escape. He is not the only one who improvises. Alba's customs officer makes novel use of her high heels in a particularly grisly fight sequence.

In spite of the rapidly mounting body count and scenes of crucifixion and disembowelment, it is very hard to get offended by Machete; this is throwaway entertainment, likely to be quickly forgotten by audiences.

There is nothing wrong with the performances. Lohan is very funny in her cameo as the brattish would-be model, April. Johnson has a manic glee in his eyes as the crazed vigilante Von and Alba and Michelle Rodriguez (last seen in Avatar) make impressively doughty action-heroines. What the film utterly lacks is any emotional depth. The characters are strictly comic-book creations. Whatever happens to them – whether their family members are killed in front of them, their own limbs are lopped off or their eyes shot out – they don't seem remotely bothered. If they don't care, why should we?