SPOILER AND GEEK ALERT!
Well, weirdly, somehow the final episode was at once very satisfying and very unsatisfying. The battle portion was great. Even most of the Earth part was good. We said goodbye to the characters in an emotionally satisfying way, although the idea of the Colonials being the source of Greek mythology makes no sense, considering the fact that they arrived about 140,000 years before the emergence of Greek myths. Also, the whole "God did it" thing is unsatisfying. There were so many unaswered questions here (like what's the connection between the Lords of Kobol and the Cylon God). Maybe some of this will be addressed in the prequel Caprica, but I doubt it.
Anyway, I made up my own answers for the unanswered questions. I used some background from the original series and shifted it around to suit me. Here's a time-line:
- 22,000 BCH (Before Cylon Holocaust): A reptilian race in a far away galaxy creates robots which rebel against them and wipe them out completely. The robots then go on to attack Humania, the only other inhabited planet in that galaxy. A one thousand year war begins.
- 21,000 BCH: The Humanians, a humanoid race (though not human), create their own robots to help them in their war. However, their own robots turn against them and join the original robots. The war ends in mutual annihilation, with all robots destroyed completely, and of the Humanians only 50 people aboard the Starship Kobol survive. They see that their race cannot survive through regular reproduction, so they invent resurrection technology.
- 20,000 BCH: Humanians settle upon a planet in the Milky Way Galaxy. They name it after their ship, Kobol.
- 18,000 BCH: Humanians find our Earth and primitive homo sapiens. For some reason, they decide that genetically engineering biological creatures would be safer than building robots, so they take a few thousand bone samples and try to guess how they'd naturally evolve. They call the homo sapiens Humans, after their original planet. They place them on twelve different locations on Kobol, which would later become the basis for the twelve tribes. The Humanians come to be known as the Lords of Kobol and are thought to be gods by the humans.
- 4,400 BCH: El, one of the few offspring of the original 50 Lords of Kobol, is born.
- 4,100 BCH: Humans create Cylons. The LOK are pissed, but El convinces them not to do anything.
- 4,000 BCH: A human scientist discovers that Cylon resurrection technology can be used on humans as well. The Lords of Kobol kill him before he can announce his discovery and prevent him from downloading into a new body. They decide to banish the Cylons. El is furious and leaves Kobol with them. Also joining him are five human priests who worship the Lords of Kobol.
- A few months later: The Temple of Hopes in established, where the Cylons and the five human priests pray to the Gods. They later find Cylon Earth. A few homesick Cylons take the last remaining FTL-capable ships and return to Kobol. They are the source of the information on Kobol about Earth and the Temple of Hopes. However, the LOK distort the story and make it sound as if El made the Cylons create the temple for himself and the five priests. He would use this distortion a few centuries later to reveal the identities of the Final Five (who don't really have anything to do with the five priests).
- 2,000 BCH: The Cylons create robots who attack them. The humanoids and the robots destroy each other. El, though, saw it coming because of the previous encounters with robots, so he warned the Final Five. He builds an FTL-capable ship for them, but the Lords of Kobol destroy it, so the Final Five must use a subluminal ship.
- Meanwhile, El returns to Kobol, and the Lords of Kobol, in their panic, decide to banish the twelve tribes (plus the remnants of the Cylons who returned to Kobol, which is why sometimes it is said that the 13 tribes left at this time). Athena, who disagrees with this decision, disables her own ability to resurrect and commits suicide.
- 1,990 BCH: A solar system with 12 inhabitable planets is discovered by the 12 human tribes. Meanwhile, the Kobolian Cylons go in search of Earth. Unfortunately for them, they never find it and die out.
- Towards the end of the first Cylon war, the final five finally reach Kobol, but find it abandoned. They mysteriously find a ship identical to their own orbiting the planet. They discover it is a jump-capable ship with the coordinates to humanity's current location. The Lords of Kobol, who had come to regret their actions of 2,000 years earlier, are the ones who secretly provided the ship.
- The Lords of Kobol and El partially reconcile. They both manipulate humanity, sometimes with the same goals in mind, sometimes with conflicting goals.
- When Kara Thrace is killed in the maelstrom, the LOK recreate her body and viper on Earth, and then downloads her into a new body. El, on the other hand, is the one who turns on four of the Final Five with the music.
- When the Colonials reach our Earth, the Lords of Kobol make her see her father one last time, and he tells her it is her time to go. She says so to Lee and disappears. She's actually taken to the LOK's ship, because they believe she deserves an explanation for everything that happened. She dies on the ship and is taken to Kobol to be buried.
- Colonial culture was lost, and all we got from them is DNA. However, the LOK manipulate things so that their names come up in Greek mythology.
- Head Six and Head Balter in Times Square don't really exist. It is just a representation of El's internal thoughts, using the images he made Caprica-Six and Baltar see. He himself has a side of him who thinks humanity will succeed and one side that thinks they won't. He's also joking with himself about how people see him as a god.