Is the "preview" they showed recently just the beginning of episode 1 or something else?
Yep. There's some speculation whether there will be any post-production stuff added before the premiere (music, CGI, etc..), but it looked finished to me. In fact, the
lack of music makes the scenes north of the Wall spookier IMO.It'll be interesting to see how the continuity goes from episode to episode since there are multiple writers working (Martin himself wrote one of the later season one eps).
In any case, I think this is gonna be a good one. I haven't followed a series on TV in years, but I'm all in on this.
And, of course, fanboards are already going nuts over changes from the books to the TV show ("her fingernails aren't long enough!", "his sword should have one more rivet in it!").