Let's hand it to Guillermo Del Toro (2008's "Hellboy II: The Golden Army") for one thing: he has managed to co-write, alongside Travis Beacham (2010's "Clash of the Titans"), and direct one of the very few potential blockbusters during the summer of 2013 that isn't based on any kind of pre-existing material or proven name brand. It's not a comic book adaptation. It's not a sequel. There's no theme park ride, and, thank goodness, no old TV series to reimagine. The plot itself might not be the most original idea to ever pass through Hollywood, but at least the onscreen world and apocalyptic mythos it creates come freshly from the minds of those who conceived the picture. Not just anyone could have convinced Warner Bros. and Legendary Pictures to fork over $180-million for such an expensive gamble, so credit Del Toro for earning the pull and reverence for major studios and production companies to be willing to take the risk. If "Pacific Rim" is admirable for this very fact, the positive tidings mustered up by the film itself are sadly short-lived. Were it not for the filmmaker's audacious rolodex of imaginative details and crafty Easter eggs he fills virtually every blink-and-you'll-miss-them frame with, this epic sci-fi showdown between Kaiju and Jaegers (read: giant beasts and robots) would be an entirely hollow cinematic experience that, shockingly, is no more comprehensible than the average Michael Bay crunch-'em-up.

The invasion began in present-day San Francisco, an underwater portal between dimensions unleashing a gargantuan monster that destroyed the Golden Gate Bridge and much of the bayside city. As more and more creatures began popping up across the globe from out of the ocean, Pan Pacific Defense Corps, led by Marshal Stacker Pentecost (Idris Elba), created 250-foot-tall, dual-piloted mechas to fight back. The humans seem to be winning the battle seven years later, but things take a sharp downward turn when hot-shot pilot Raleigh Becket (Charlie Hunnam) loses his older brother Yancy (Diego Klattenhoff) in a brutal showdown off the coast of Alaska. Five years later, circa 2025, Raleigh is a lowly construction worker putting up a barrier wall around Hong Kong when he is approached by Pentecost to rejoin their team. With only four robotic Jaegers remaining before their funding runs out and more Kaiju lying in wait, he needs his best warriors to lead the final do-or-die fight to save humanity.

The 18-minute, pre-titles prologue that gets "Pacific Rim" off and running is as arresting as the film gets, economically introducing the audience to an alternate reality where the planet is under siege from invading behemoths and the initial steps we take toward defending our turf. The use of the Jaegers is a convoluted process called Drifting, wherein two people man the controls from inside the helmet of the mecha, the thoughts inside their heads paired up so that they can seamlessly control the gigantic steel creation together. It sounds like it could get confusing, but it never does. The opening Alaska-set action sequence, taking place in the midst of a hurricane as Raleigh and Yancy attempt to save a boat crew from one of the monsters, is frenetic but involving, skating along on the early spectacle of its imagery.

With the exception of a riveting flashback later on depicting a traumatic memory from Japanese pilot Mako Mori's (Rinko Kikuchi) childhood, never again is director Guillermo Del Toro able to capture the sheer threat and frightening wonder of his otherworldly villains. More "Transformers" than "Cloverfield," the battle scenes quickly become repetitive and pedestrian, detrimental sensory overloads that absolutely scream out for the camera to pull back and take in the entirety of its would-be awe-inspiring sights. Instead, the action falls right into the trap that Michael Bay is so often guilty of, misplacing crucial tension, momentum, and coherence for a bombardment of swirling metal and swinging body parts. Del Toro really should know better than this, for it's the overriding fatal flaw that ruins one's enjoyment of the finished product.

The central characters are presented as one missed meal away from barebones, their development too minimal to justify the amount of time spent with them in the first half. Charlie Hunnam (2006's "Children of Men") has the good looks and easygoing flash of charisma to play the main character, Raleigh, but he, like much of the cast, tend to get lost in their CGI-heavy surroundings. The grief he feels for having lost his brother is touched upon, then dropped. As his new partner and co-pilot, Rinko Kikuchi (2012's "Norwegian Wood") gives a great deal of honesty to her role of Mako, but one can tell that her dialogue was either minimized because English isn't her first language, or it was a casualty of the final edit. All the same, the amount that Kikuchi expresses with her face alone is only surpassed here by her younger counterpart; playing the child version of Mako, newcomer Mana Ashida is nothing short of exceptional in a brief but emotionally draining part that puts her through the wringer.

As Marshal Stacker Pentecost, Idris Elba (2012's "Prometheus") manages the difficult task of being stately, stern and inspiring without going for jingoistic, rah-rah histrionics. All the same, he intends on cancelling the apocalypse. Supporting players of note are mostly of the comic relief variety. Charlie Day (2011's "Horrible Bosses") and Burn Gorman (2008's "Penelope"), as overeager scientist Dr. Newton Geiszler and his socially awkward assistant Gottlieb, remind of over-caffeinated dunces at best and Looney Tunes characters at worst. They're really annoying. As for Ron Perlman's (2011's "Conan the Barbarian") black-market monster parts dealer Hannibal Chau, he is a welcome addition when he first comes on the screen, then gets little to do beyond spit out the occasional one-liner.

"Pacific Rim" is one of the year's biggest disappointments, a motion picture of colossal scope but piddling overall emotion that sends eager viewers into fast-fatigued submission. Del Toro has an undeniable eye for detail—the way the buildings of Hong Kong have been rebuilt around the skulls of past monsters is an ingenious touch, for example—but most of the goodies buried in the film will likely be appreciated more once a person can watch it frame-by-frame on Blu-ray. Moving at regular speed, the movie is so antsy to get to the next shot that audiences aren't given the chance to drink it in or feel, well, much of anything. Additionally, Del Toro botches the results of action scenes too large in scale for him to properly choreograph and handle, and the effects work suffers because of it, too; there's massive destruction on display, to be sure, but that's all it is—a lot of falling buildings and loud noises and chaotic, difficult-to-see creatures and robots getting throttled with next to no responsibility taken for the true damage done and lives lost. Where is the terror? Where is the suspense? Where is the beauty? The majesty? The sense of loss? A viewing of "Jurassic Park" for all involved may have been an invaluable tool before filming got underway. "Pacific Rim" is a pretty, dumbed-down shell of a movie. It could have been so, so much more.