So Moses did literally split apart the sea, send the plagues to Egypt and see the bush of fire and Jesus did walk on water and come back from the dead, literally... but the talking snake is an allegory. Is that correct?

Exactly. Generally, a text is either allegorical/symbolic or literal; rarely is a text both. In the former case, it is a work of fiction; in the latter, it is considered as some factual document. The Bible is the only book with varying elements of the former and latter that differ according to whom you ask, particularly Christians. For an organized religion, they damn well have a poorly organized literary view of the Bible.

Most christians here believe that the bible merely holds a certain meaning that still applies to us, even after 2000 years. The bible was written in a language that is hard for us to understand as we don't have the knownledge of what life was 2000 years ago - even if we understand the words, we may misinterpret the meaning. It's unclear to me what they actually find from bible that common sense doesn't say to a believer; why do they think a book with horrible cruelty and injustice plus a hidden meaning that is still supposed to apply to humans is somehow holy. It's not the contradictions and hypocrisy of the bible, but rather the illogical relationship between the bible and the religion, along with the subjectivity of god, that worries me about Christianity.