"Pacific Rim" was not a big hit out of the starting gate last week, and perhaps that's understandable. Unless you are a fan of the "Godzilla"-influenced branch of Japanese popular cinema, the story of ferocious creatures called Kaiju facing off against massive robots called Jaegers may not sound all that appealing. Yet underestimating filmmaker Guillermo del Toro and what he can do on screen is something done at your peril. He's so accomplished a creator of images, so adept at humanizing the monstrous, so fearless an architect of awe, that the scenarios he throws himself into are invariably difficult to resist. "Pacific Rim" very much lives in comic book/pulp science-fiction territory, but Del Toro's skill and attention to detail combine to make it a deeper movie experience.