Every moment of combat in Pacific Rim is the visceral, heavy action that makes the climaxes of Gunbuster or Getter Robo Armageddon so satisfying; the enemies have the body-horror surrealness of the Invaders or STMC, the machines are breakable yet visually heavy and powerful. It captures well the ritual and tradition of its genre - the launch sequences that take the real-world idea of preflight checks and turn them into elaborate mechanical ceremonies to venerate incomprehensible technology.
NOTE: THIS ARTICLE CONTAINS MINOR PLOT DETAILS FOR PACIFIC RIM, AIM FOR THE TOP! GUNBUSTER AND SHIN GETTER ROBO VS NEO GETTER ROBO.
Perhaps most crucially the combat is paced well - the slow movement is made urgent and the confusion of battles fought through the medium of a machine is used to good effect. In an interview prior to the film's release, the mechanical nature of the robots in it was highlighted - how the design cues came from mecha films and series like Tetsujin 28 and Patlabor. This emphasis is clear in how the fights play out - there is a physicality to them, little of the light-touch playfulness of more superhero-like mecha. Failed attacks connect rather than explode harmlessly against armour - the enemy creatures and the protagonists alike are buffeted about by the colossal forces behind each punch or slam. Mounted weapons and biological attacks wound aliens and wreck robots. Indeed, the very first fight - in which the "headline" robot, the Mazinger Z-esque Gipsy Danger, suffers extreme damage - makes this incredibly clear while being itself a kind of homage to any number of glorious sacrifices in mecha; its pilots could be Musashi in Shin vs Neo Getter as they fight on regardless of damage. Immediately from this opening Pacific Rim sets out what kind of super robots it seeks to emulate - the almost terrifying, unstoppable war machines, not the brightly-coloured superheroes. Yet this kind of a subdivision is not entirely useful; in both narrative and aesthetic terms, the film draws on both archetypes and its closest plot parallel is really Shinkon Gattai Godannar - probably the archetypal modern reimagining of that knockabout genre. The robots in Pacific Rim have the special moves that a super-robot should have - chest gun batteries and blasters, oversized blades and the iconic rocket-assisted punch. The end result when Gipsy Danger fights is, in fact, closest to something like Black Getter or Godannar - the fight has it switch between weapons and basic brute strength at will, rather than cycle through lists of ineffective attacks. This continues when the other robots fight - Cherno Alpha has weapons which increase its physical strength and fights like Giant Robo or The Big O, as one example.
So there is much to like about the combat, and the way in which the action plays out; the final battle, fought blindly in a hostile environment feels heavily inspired by Gunbuster - as much the title machine's triumphant first deployment as Noriko's first blind fight in which Smith dies. Yet a super robot series - a good one - is never just about the action. To return to Gunbuster - a series which has much in common with Pacific Rim in the nature of its setup and conflict - what matters, what keeps the viewer watching and what makes the combat so cathartic is Noriko's journey and what brings her to fight. Without the emphasis on the pilots, without a believable journey for them, a mecha story has no reason to watch save contextless action. This is what drags down examples like Mazinkaiser SKL or Dangaioh; while the action is dynamic and on a par with other examples, there is no motivation to watch. Pacific Rim is not that bad. There is a personal element and it is one heavily drawn from the super-robot genre - the non-action scenes have comedic scientists that seem to grasp at emulating the three professors from Mazinger Z while the base commander is evocative of Aquarion's Gen Fudo and Gunbuster's Coach Ohta. But none of it hangs well together; the inter-personal conflicts are the sort of stuff that would be heightened and clichin a super robot series (crises of piloting confidence, brash aces conflicting with untested recruits) but there is none of that heightened emotion that is needed to have the plot zip along. Everything is presented in a way which strives for entertaining melodrama (for super-robot stories thrive on that) but feels too serious to fit a setting based around super-robots. The entire tone and aesthetic of the base scenes - grimy rusted corridors and constant mistrust and desperation - is straight from something like the remade Battlestar Galactica and the inspirational scenes - arguably the dramatic climaxes of super-robots not involving super-moves - keep up this kind of bombastic resignation.
This is not to be too redemptive of most super-robots in narrative terms; examples like Gunbuster which do genuinely interesting things with the cliches of character development are comparatively rare. Yet it is ultimately better to have simplistic motivations and not sacrifice the sense of movement of the story than to awkwardly attempt more. Everything in Pacific Rim to this end feels perfunctory and unambitious in execution, not intent, and as a result unsatisfying. It is this ultimately underwhelming (yet still capable) attempt to make the story personal that drags it down as a complete film; since the pilots as characters are perhaps underdeveloped (not for want of trying - indeed the underdevelopment feels a result of a superflux of super-robot archetypes and scenes being crammed together and no single one really standing out) there is not the same kind of narrative catharsis as when Noriko finally talks Kasumi back into the fight against the STMC; the ultimate conclusion of the personal stories, when there is a moment of sacrifice at the end of the film, evokes Musashi's destruction of the Getter in Shin vs Neo Getter - an action-climax to show the seriousness of the situation - rather than the conclusion of a compelling (even if simplistic) character arc.
Overall, Pacific Rim is a highly enjoyable film and a much more ambitious action blockbuster than most. Even if it does not directly homage any single mecha anim , and even if those homages identified above are not entirely intentional, the influence is undeniable and a fan will see parallels - arguably a sign that it is a film made well in knowledge of its sources. It remains a hair's breadth from being truly great either as a super-robot story or action film, however, because its non-action scenes seem underdeveloped. It is not fair to expect every super-robot series or film to stand up to the highs of the genre in terms of development beyond action - The Ideon: Be Invoked, Gunbuster, Giant Robo or Eureka Seven - yet what the most solid and enduring examples do is keep to a simple arc (for example Gurren Lagann's journey for Simon) and make it memorable. Indeed, comparing a TV series to a feature film seems counterproductive - but even something like Macross: Do You Remember Love or Macross Plus is able to better create a memorable yet simple character arc.