Ah Zeitgeist. Yeah it confused me too when I first watched it. But interestingly SO much of it has been debunked and so much of it is either bad scholarship or outright false. Many of the comparisons they use refer to different languages and they apply it to English.
For example they say that the term Sun Set comes from Horus being the Sun God and Set (meaning darkness) being his brother. That doesn't work. For a few reasons. Horus is NOT the Sun God. Osiris is. SETH was not Horus' brother but his uncle. And Seth was not the God of darkness but the God of storm. The actual fight between the sun and night was a fight between Ra and Apopi. Bad scholarship. Another reason is that Sun and Set are english words that do not refer to either Horus or Seth.
They also try to tie Horus in with Jesus. They use MANY inaccuracies in this attempt as well. Here is a well dictated response by a historian about Zeitgiest:
http://www.youtube.com/watch?v=aPmY1f9_d3M&feature=related
A few examples of this is that it is claimed that Horus mother was a virgin. False. Isis, Horus mother, had regular sex with Osiris and used a golden dildo. He was not called the Lamb of God but was called the Hawk. Horus never died. His FATHER died and was dismembered by Seth, and was resurrected by Isis. The claim that Horus was born on December 25th marked by a star in the sky, was worshipped by 3 kings, had 12 disciples, was baptized and crucified...ALL LIES. This claim was based off of a poet named Gerald Massey, and this was shown to be 100% false.
Zeitgiest also tries to connect Jesus with Attis, saying that these same events happened in his life. Again, bad scholarship and outright falsities. Attis was not a sun god, nothing is stated about him being born on Dec 25. He killed HIMSELF and he never did rise again. Again, lies.
Again the connection is attempted with Krishna. He also was not a sun god, was not born on Dec 25, was not born of a virgin (was actually the 8th son of Devaki and Mathura), Died from an arrow wound in 3102 and was never raised again.
Another connection was attempted with Dionysus. Again, he ws not a sun god. He WAS the god of wine, but the connection to Jesus stops there. He was NOT born on Dec 25, was dismembered by Titan and resurrected by Apollo. He had hundreds of FEMALE disciples.
Another connection was attempted with Mithra. He was not a sun God, he was born on Dec 21st, was born from a rock, never died, and did not have any disciples.
Trying to connect these with Jesus is imaginary. For one thing celebrating Jesus birth on Dec 25 was the invention of Pope Liberio in 354 and was not a teaching of Christianity. In fact even Pope Liberio did not say that Jesus was born on this date, but that we would celebrate it on this date since we do not know when Jesus was born.
Possibly the SILLIEST connection that Zeitgiest tries to make is to compare the SUN to the SON. If you watch the video above you will see how ridiculous this is. It's an bad English pun and does not work.
Finally, I want to post this response to Zeitgeist. It thoroughly debunks this shockingly inaccurate video. I would educate yourself on this before you let this video confuse you.