Throughout his career, writer-director Guillermo del Toro has capably balanced pulp sensibilities with high-end art, and the result is a filmography that is fanciful and highly enjoyable.  With “Pacific Rim,” Del Toro throws his more serious side out the window to make a big-budget spectacle that pays homage to giant-monster movies like “Godzilla” and “Gamera.” The premise of the film is as silly as one would expect, but that’s OK. Del Toro has fun with the material and, as a result, the audience does, too.