Forty years ago the citizens of Paradigm lost all of their memories, and live their lives without any knowledge of their past, or any hope for the future. Roger Smith is a man who performs the much needed task of negotiator in Paradigm. He provides his services to the wealthy with the help of a peculiar android named Dorothy and his mechanically inclined butler Norman. When greater evil arises, he calls on his magnificent relic of Paradigm's past, the Megadeus Big O. With Big O at his side, Roger Smith may be Paradigm's only hope of surviving in this new world without memories.
In an experimental city of despair and carnage, ORGAN will do anything necessary to gain power and wealth. Unfortunately for one underground boxer who was mutilated, a rogue doctor has given him what ORGAN specializes in and he despises: Texhnolyze body parts. Will these cybernetic appendages help exact his revenge upon the one who made him this way?
Both anime share a very particular ambiance, and are a mix of action and the portrayal of a world's meaning and past. Both main characters are led to seek the past of their world to find solutions to the current situations. The graphical style is very different, Big O being closer to American animation, but the underlying ideas are quite similar.
The eccentric Suzumiya Haruhi wants nothing more than to meet aliens, time travelers and espers… but she’ll have to settle for the everyday Kyon instead! Along with the mysterious Itsuki and the vacant Mikuru, the duo forms the SOS Brigade – a club whose mission is to discover the mysteries of the world. Armed with a razor sharp wit and a skill for manipulation, Haruhi will stop at nothing to have fun at all costs, even at the expense of Mikuru’s dignity!
Postmodern fiction is known for being a self-referential, non-linear hodgepodge. The Melancholy Haruhi Suzumiya and The Big O are good examples of this movement.
Haruhi Suzumiya and The Big O manage to combine disparate genres without missing a beat. The former is an absurdist high school comedy; the latter is a mecha neo-noir. Like Tarantino's Pulp Fiction, these shows make extensive use of homage and pastiche. The Big O is a tribute to the Japanese and Western cinema and television of the 1960s and 1970s, while Haruhi Suzumiya is layered with innumerable pop culture references, from Stoppard's Rosencrantz & Guildenstern Are Dead to Capcom's Ace Attorney series.
Keeping with the postmodern sensibilities, both have moments that play with the line between reality and fiction, like Roger's line ("I'd have to say you have the wrong guy. I'm not exactly a bounty hunter.") in Act:17, a reminder of the voice actor's turn as Spike Spiegel in Cowboy Bebop, and a poster of Aya Hirano ("Haruhi"), Minori Chihara ("Yuki") and Yuko Goto ("Mikuru") in "Mysterique Sign".
If you like your anime unconventional, look no further than these two.
A man awakens in an unfamiliar room, with no recollection of who he is or where he came from. His wounds have been bandaged, and his face is covered with a mask that he cannot remove. With nowhere to go, he decides to stay with his rescuers and help them when needed, waiting for his memory to return. Though his courage, skill, and wisdom quickly gain him the villagers’ respect, the same traits soon land him in hot water with the local feudal lord. Not one to back away from injustice, the path he must follow will lead him to confront his enemies, and his hidden past.
Somehow Big O felt similar to Utawarerumono. I just can't name what made me think so. If you liked one, you can try watching the other as well.
P.S. Keep in mind that one is a mecha show (with poor story) while the other is a fantasy (with a hint of harem).