Imagine if the first 30-50 minutes of Speed Racer were devoted to explaining what a 'car' is, and why people were racing them. "I was fifteen when I saw the first speed race... They called them automobiles... Driving very quickly... We built them because horses were too slow..." Just interminably. That's Pacific Rim.
Del Toro fans might recall how Hellboy 2 unceremoniously ditches the bland human audience-identification character from the first film, having Hellboy and the other monsters go rogue from their government organization to have wild pagan monster adventures. Imagine if they killed off Hellboy instead. That's also this film.