Had director Michael Bay been around in the Middle Ages he probably would’ve made quite a living performing experimental operations on the brains of conscious patients. While the times may be more civilised, and the tools of a different trade, with Transformers: Revenge of the Fallen, Bay proves himself equally adept by administering the cinematic equivalent of a lobotomal procedure.

Picking up the narrative two years after the events of Transformers, the Autobots have now formed a top-secret alliance with the U.S. Military as N.E.S.T (Non-biological Extraterrestrial Species Team) to combat the Decepticons, who continue to wreak global havoc (from which most of the public has remained curiously oblivious).

Meanwhile, the hero of the first film, Sam Witwicky (Shia LaBeouf), is preparing to leave home and girlfriend Mikaela (Megan Fox) for college. That is, until he comes in contact with a shard from the AllSpark (the mystical power cube thought destroyed), and once again he’s drawn into an inter-planetary alien war which threatens to destroy the Earth.

Not unlike its predecessor, the plot of Revenge of the Fallen is little more than a paper-thin pastiche of generic filler, ripped piecemeal from the narratives of other contemporary sci-fi, action-adventure, and war films (from Indiana Jones and King Kong to The Matrix and Black Hawk Down) but it does so without any real sense of continuity, pacing or drama.

Admittedly, Bay’s not attempting to re-invent the wheel with this film but when neither the action nor the comedy (which consists entirely of fart, testicle, and humping dog jokes – all of which misfire) ever reach great heights, Revenge of the Fallen’s near two-and-a-half hour running time makes for an interminably mind-numbing experience.

Likewise, the film’s crowning achievement, the digital imagery, is only intermittently impressive. When Bay pulls back from the action to allow the audience a recognisable glimpse of the battle sequences the result is praiseworthy, but too often he keeps the camera in close and on the move, rendering the various Transformers an indistinguishable mass of moving metal.

Yet perhaps the biggest shame of this Transformers outing is that despite his admirable efforts, the clear talent of Shia LaBeouf is once again muted by an unimaginative script and poor direction. The same might be said for Megan Fox, who is left to pose through the entire film either draped over machinery like a Chiko Roll girl, or else pouting towards the camera.

Even diehard Transformers fans for whom the tagline, “more than meets the eye” has long held a nostalgic sentiment, might, at least on this occasion, do well to avert their gaze. Your brains will thank you later.