Wow, that finale was fantastic, though I am hating myself for staying up to midnight to watch it "live". Let's see... spoiler-free observations first:
Was that the first time we had seen the opening credits? Or was that just new? In the very first episode there was an opening-credits thing, but I'm pretty sure it wasn't as extensive as this was. And in the subsequent episodes I think we got a title-card and that's about it. The credits that they showed this time were sort of a mixed bag -- some of them were a nice intro to humanity's expansion into the solar system, and some of them looked like they were going for a "fake" look, sort of like GoT, which I didn't think fit too well. No big deal one way or the other.
I liked the opening sequence showing Julie Mao's POV of the whole thing. It managed to clarify a few things, though not anything that was a massive mystery or that really needed clarifying. It was just a decent recap of the season. There was one aspect of it that actually raised some questions for me, and I'll address that in spoiler tags later.
The Earth-based stuff was mostly "meh" with the exception of the cool pencil thing. The "twist" with the villains was not all that twisty, and I do kind of wonder why - with all the obvious care that has gone into their evil plot - the bad guys left such an obvious breadcrumb trail back to the shipyard. Especially when we've seen that it's not too difficult to alter "drive signatures".
The acting was a little spotty in places. The guy that plays Holden (Steven Strait) had some really flat deliveries here and there, as did Avasarala (Shohreh Aghdashloo) and Naomi (Dominique Tipper). I don't really blame the actors so much as the director - it seems like these were lines that would have been easy to fix with one or two more takes. Maybe they were running out of time/money. That criticism aside, the acting was fine overall.
I really enjoyed their (fairly) realistic take on radiation poisoning and I'm really pleased that they didn't decide to go with some cheesy green glow or whatever to hand-hold the audience into knowing that bad radiation-stuff was going down. Miller's utter confusion as to what had just happened and the fact that there were no immediate effects was great.
I continue to like Amos' amoral actions. In the books he is aware that he needs an external moral compass, and that is reflected in the show as well, but the show-Amos utterly sociopathic attitude towards killing and corpses goes a bit beyond Amos in the books.
And the Miller/Holden pairing was just as good in the TV show as it was in the books. Their discussion in the game parlor (and really the direction in that whole scene) was great. And I liked Miller's gleeful interaction with the "gangster" guards. "Let's get this man some medical attention!"
Just in case
The one thing I didn't understand with the whole Julie Mao recap was the fate of her message to Anderson. Her first message obviously got through because Fred Johnson sent Holden & Co. out to the coordinates she sent. But the second message asking for help, sent from Ceres... why wasn't that acted upon? Did Anderson not get it? Got it and decided not to act on it?
I'm very pleased that they significantly toned down the whole "space zombies" thing. That was easily the weakest thing in the book. Simply making them desperate sick people was effective without making them seek out the living to puke on or whatever.