I know some might disagree with me, but honestly I felt the first season was a 10/10.
I still recommend the first season to anybody who will listen. I was mesmerized by the dark mystery that was Big O, and when I heard Cartoon Network was going to fund a second season I was ecstatic.
Unfortunately, I hated the second season. I felt like everything changed, aside from the characters. It had a different feel, and I felt like it had a completely different story line than the first season. The ending seemed as if it were a cop-out ending as well. I failed to anticipate or appreciate its direction.
I left Big O irritatingly confused. Perhaps I'll re-watch it with some friends and we'll pick it apart. Until then, 5/5. I would love to see a remake of the series.
