I believe the stories, such is Abraham taking his son right up to the point of sacrifice at the altar, and the Flood, but I think much of Genesis and Revelations, regarding the beginning and end of the World, is metaphorical, inspired by the Holy Spirit.
Where it reads "Let he who has understanding count the number of the beast...", it hints that it is a metaphor to be unlocked. I think that kind of reading is required throughout.
Re: the mark of the beast. I believe this may be an actual mark, but I have a friend who says that some may be so busy looking for the antichrist that they will miss the fact that he has set up his temple in their own hearts -- i.e., those whose thinking is just like the world.