There is a tendency in writers to edit the first chapter, quite a few number of times. Especially after the whole thing is clear in the writer’s mind.
This is not necessarily a good practice. Because after the book’s been written, a writer is more aware of what the book is than the reader. Therefore, when he edits the first few pages, he tends to get a little extra intelligent, thereby exhausting the reader’s patience by it’s obscurity.
The typical reaction to such a book would be, “The first time I read it, it was good. The second time, it was even better.”
I do not consider it as a compliment necessarily. (I as a reader do not have the patience and the humble ego, to continue with a book that I don’t like, and more importantly to read it again.)
And also, this effect is very often confused by the reader, and he/she thinks the book to be high art. Since the first time, it was not very easy to get.
As a writer, the choice is yours as to what you want to do, but my belief is that the first chapter should be more revelatory, than explanatory (justification for what is to follow in the book, i.e.). And also it should be gratifying, without being gimmicky.