The Big O is truly a special anime. It is both deep and action-packed, thought-provoking and exciting. The Big O is certainly an anime any fan of giant robots should pick up, and its great characters may draw fans who might not necessarily like mecha anime.
Big O is noteworthy in that it is one of the very few series to get a sequel because the American audience demanded it. The series was originally going to be a measly 13 episodes, but the fans complained because of the huge cliffhanger at the end of the last episode. Cartoon Network heard their plea, and produced another 13 episodes of the series.
In my opinion, the second season is not quite as good as the first. The storytelling and art are not done in the same fashion as in season one. Whereas the first season used drab colors to convey the sense of hopelessness and despair in Paradigm City, season two abandons this in favor of more vivid and bright colors. However, this is by no means bad, as the new animation and coloring looks exceptional. It just doesn't convey the grunginess of Paradigm as well as the first season did. The storyline is presented in more of a coherent narrative with each episode directly tying into the next. This was my major problem with the second season. I loved how the first season gave you bits and pieces of the overall story through each individual case Roger Smith completed (or failed to complete). It gave the series a great amount of depth.
The episodes themselves are incredible, however, and the last four are among the best of the entire series. Some moments are absolutely breathtaking, such as when Roger faces off against a rebuilt Big Duo while racing against the clock to save Dorothy, or when Roger finally reveals the true power of Big O in the final episode. The episodes flawlessly mix plot development with great battles.
One of the greatest things about Big O that makes it a timeless anime classic is the storytelling. Big O tells an epic mystery story, and it does it with style. The great thing about this series is that it is one you can really discuss and have different theories on what exactly happened. The series has this habit of blowing everything you previously thought right out of the water in a matter of minutes. And, like the ending to season one, the ending to season two simply presents more questions rather than answering everything.
As always, Big O has incredible music, especially in these last episodes. The heroic battle themes and brooding, driving choruses truly set the stage for the epic finale. Overall, it's a treat to listen to.
Big O is an anime I can recommend to any fan. It has all the things that make anime great: deep characters, a great plot, incredible action sequences, and good music. If you watch Big O with an open mind and ponder the many things that happen, I'm sure you won't be disappointed.