I enjoyed episode 1 and 2. They each had their flaws but were generally enjoyable and served their purpose of quickly conveying information to set the table for the series.
Oddly, I found episode 3 and the battle to be my least favorite episode. A lot of the action lacked tension. As a result, it felt overly fake. I'm not entirely sure how to explain that. How everything fit together came across as contrived.
The dire situation of the war lacks gravitas. Despite exposition telling me how bad things are, I don't believe it, and it doesn't seem that most of the people on screen fully do either.
The ensuing battle then undercuts any seriousness which may have existed by showing Crabfeeder's forces as a (momentary) combination of incompetent and poorly led. As that's the only time the audience sees Crabfeeder and his forces, there aren't any other scenes from which ideas about the enemy can be drawn.
I believe the intent was to try to show Daemon as badass during his beach charge, but it had the opposite effect for me. By taking away any of the elements which made Crabfeeder a competent adversary, you also undercut the value of the protagonist's victory. All of that is then followed by a flat and unsatisfactory end to the situation.
I'm not sure how it is written in the books. But how it was filmed and choices about what to show or not show didn't make a lot of sense. The second half of episode 3 felt disjointed and confusing.
Not every episode can be great. That's true of any show. Even so, the third episode was a bad time to have a dip. The first two set the table. Then kinda nothing happens.
Another thing I've noticed is a lack of a character or a performance to rise to a higher level. For example, Charles Dance's portrayal of Tywin was phenomenal -elevating both the show and everything around him. While there are no performances which I would say are bad in HoD, a few come across as lesser versions of other characters. Matt Smith's Daemon started out as a bright spot, but the flat ending of episode 3 didn't do it any favors.
Hopefully, it's just one stumble along the way of finding the show's footing. I think how episode 4 recovers (or doesn't) will echo throughout the rest of the show.