A new TV show's opening credits sequence is often one of the last things completed, and therefore something critics don't always get to see before a show debuts. I don't know that the title sequence for "Manhattan" — which WGN America just renewed for a second season — would have significantly upgraded my initial review of the show, but it does a nice job of suggesting the level of ambition and execution the show would be able to achieve over the course of its first season, which concludes Sunday night at 9.

That title sequence (you can watch it here) presents an overhead view of a series of sketches and diagrams, as the military base that housed the Manhattan Project is rapidly constructed in the Los Alamos desert. We start with some solitary workmen, then blueprints of houses, then the houses themselves, with plans being mixed with physics equations and desert recipes and propaganda fliers, all as the base gets bigger in a damn hurry, full of people and buildings all there for the sole purpose of building the world's first atomic bomb. And as the music builds, we see the entire population of the base known as "Nowhere" clustered together before the grouping expands then contracts — moving very much like one of the bomb designs being proposed by the show's two competing science teams.

It's a visually neat way of conveying both the story and themes of the series, which has dealt nimbly not only with the moral questions associated with building such a destructive weapon, but with the diverse lives and backgrounds of the many fictionalized scientists, soldiers, wives and other hangers-on whose lives have been upended by the attempt to build the thing.

The pace of the series has at times been slower than what's suggested in those opening credits, but usually in a rewarding way. The first episode introduced us to the two rival science teams — one a band of misfits led by the abrasive Frank Winter (John Benjamin Hickey), one a group of polished bullies, plus wide-eyed genius Charlie (Ashley Zukerman) — and made clear that inevitably, its two leading men would have to join forces. But rather than rush to that moment, the season took its time establishing the quirks and flaws of each man, and the relationship they have with the people around them, before finally having them team up secretly — after Charlie realized that his group's model would never work, while Frank's less-celebrated implosion design required manpower the government would take too long to provide — so that the characters and the world felt lived-in, rather than simple cogs of history.

And along the way, the show has told a lot of fascinating stories about the physical, emotional and spiritual cost of working on such a project, for all involved. I worried in the early going, for instance, that Olivia Williams might be wasted in the archetypal, marginalized cable wife role, but that became the whole point of the character, a strong-willed scientist in her own right who rebels against the very cable-wifery to which she has been consigned. The show has dealt with what it would have been like to be a woman, or black, or gay, in this period, mixing smart social commentary in with all the science geek and paranoid spy thriller material — often, with the recurring presence of Richard Schiff as the man tasked with keeping the project's secrets secure, suggesting the ways in which paranoia can lead to plain madness.

I grew to like the show a lot, and was worried that the low ratings might leave it as a one-and-done. Sunday's finale (which I may write about it in more detail, to be read after it airs) is excellent, and suggests that there's much more story to tell. I'm glad that WGN, still relatively new to the scripted original game, chose to stick with a series that may not be sexy, but that's turned out to be very, very strong.

Has anyone been watching? If so, what have you thought so far?

Alan Sepinwall may be reached at sepinwall@hitfix.com

Alan Sepinwall has been reviewing television since the mid-'90s, first for Tony Soprano's hometown paper, The Star-Ledger, and now for HitFix. His new book, "TV (The Book)" about the 100 greatest shows of all time, is available now. He can be reached at sepinwall@hitfix.com