AMERICAN ULTRA (15, 96 mins)

Jesse Eisenberg, Kristen Stewart, Connie Britton, Topher Grace, John Leguizamo, Walton Goggins.

Director: Nima Nourizadeh.

Released: September 4 (UK & Ireland)

SOMETIMES, weird can be truly wonderful.

In the case of American Ultra, a bonkers mash-up of a stoner comedy, spy thriller and misfiring romance, a few flickers of starchy convention wouldn't go amiss.

Screenwriter Max Landis conjures explosions of cartoon violence and heightened verbal exchanges that look and sound like they have been adapted verbatim from a graphic novel.

In fact, this outlandish caper about a dormant CIA assassin, who is hidden in plain sight as a dopehead loser, is an original concept and director Nima Nourizadeh embraces the madness with fervour.

Visually, there are neat flourishes, including a fist fight under UV lights and a shoot-out in a kitchen that relies on a precisely angled bullet ricochet from an airborne frying pan.

The tone slaloms wildly between heartfelt and hallucinogenic, ultimately proving the film's undoing.

Every touching moment between the two leads, portrayed by Jesse Eisenberg and Kristen Stewart, is invariably punctuated by a head-on collision between a meat cleaver and a forehead, or some other grisly burst of insanity.

CIA agent Victoria Lasseter (Connie Britton) presides over the top secret Ultra program from her desk in Langley, Virginia.

The grand experiment is deemed a failure and remaining assets - government-sanctioned assassins - are declassified, their memories wiped so they can lead normal lives with new identities.

Lasseter's sworn rival, Adrian Yates (Topher Grace), orders the immediate removal of remaining Ultra assets using his reconditioned mental patients from the Tough Guy program.

The last Ultra agent in the field is stoner Mike Howell (Eisenberg), who works at a convenience store in West Virginia.

"This guy is a trained killer. He is a security risk," barks Yates, deploying his gun-toting death squad.

Mike is blissfully unaware of his blood-spattered past and frets about proposing to his pretty girlfriend Phoebe (Stewart).

Lasseter refuses to stand by and let the CIA slaughter Mike so she re-activates him then watches in awe as the stoner outmanouevres Yates' psychotic henchmen and goes on the run with Phoebe.

Aided by his drug dealer (John Leguizamo), Mike learns the full extent of his capabilities and resolves to strike back at the agency.

American Ultra benefits from endearing performances from Eisenberg and Stewart, who ground their drug-addled romance in reality when the rest of the picture is getting deliriously high.

Supporting performances ricochet between Britton's concerned mother hen and Grace's snarky pantomime villain, who seems like too much of a liability to walk the corridors of the CIA.

Action set pieces are staged with tongue wedged in cheek, using a stuffed bear as a silencer for one killing and a spoon as a means to dispatch another rogue operative.

Amidst the devastation, which is captured in glorious slow motion, there are fragments of an oddly enjoyable and sweet yarn.

6/10

Damon Smith