The problem is that for a long time there was no one Bible. The Hebrew bible was written in the 6th century BCE in Hebrew, it was translated into greek in the 3rd century. The old testament was first put together in the 2 century CE, he last adjustments were mad in the 4th century.
The new testament has a similar history the first collections date to the early second century CE, but the official canon wasn't agreed upon until the very late 4 century.
The reformation changed things around again.

The important part however is that the changes do not so much affect what's written in the text but what texts are considered to belong in the Bible (others are in the apocrypha; some of those texts are a little bizzare like one that has Jesus fight a dragon, but others have switched back and forth between apocrypha and Bible ).
And the exact wording of the texts, that is especially a problem in translation, because obviously some things don't translate well. And the texts are also often modernized, the worst of the archaic language switched for something more in tune with the times or the environment.
So yes, the Bible is noticeably different, but it is also very much the same content. The stories were not really rewritten, but they have been put into words easier to understand, while preserving the content as much as possible.