They don't send just the first episode , usually they always send the first couple of episodes the first 4 in this case , for a review .
Still for everybody getting bummed about the first episode (I haven't watched it) all reviews i read were great , except the first episodes many praise this as what seems to be the best season yet (according to the first 4 episodes) . Also it seems that this season the show will part ways with the book in some ways , personally i am afraid , but reviewers seem to have liked it .