3-4 hours in, just loving it. I can see if you don't like the setting or the plot doesn't click with you that the opening few hours would be slow, but I love the story and world so to me this has been fucking fantastic since the start. I'm a slow, patient sneaky bastard in every game that allows it, so stealthing through is right up my alley. I don't think I've used any bullets since that early tutorial style bit of shooting.
Really love the characters, and as my wife said when she walked into the living room the animation is great - she asked if this game did motion capture of the actors 'like uncharted' because the facial expression and lip syncing was so good. She was also impressed with the sound during the rain storm as I avoided enemies, as was I. Loving the audio as much as the (excellent) visuals.