I am really not sure what to think about where they took the Chief and Cortana story. I'm sure they are going to explore it more in the next two games cause I don't believe for one second that she won't be back in the next game.
Unless they find a way to get her back into the fold really early in the next game, then it will probably be a "oh no Cortanas gone and let's go find her" thing. But if you'll remember, Cortana wasn't with Chief at all in Halo 3 except on the last level, so that whole sad theme of losing her is gonna feel really tired and lazy I'll bet.
Most of what I have to say has been said already, so I'm just gonna say this one thing that bothered me. At the end, when Lasky is talking to Chief, he's like " I've lost people too, but I I can't begin to imagine how this feels(in reference to losing Cortana)" or something along those lines. Ok... what the fuck is with that? Cortana is a computer program that Chief has known for maximum 4 years( cause 4 of those 8 years he was napping). Even when Lasky loses his lady friend in the Forward Unto Dawn series, that is way worse than losing some computer program, cause it's a fucking person. And he says people, not person, so obviously there's other people he lost too. He could have watched his mother die, and im sure hes seen buddy's get killed right in front of him over his lengthy military career, so how in the fuck is Chief's loss so much greater than his own? I know this is a minor annoyance compared to larger flaws in the game, but fuck me was that line ever dumb.
I just finished the episode, and while I thought it had some exciting plot twists and potential mystery, ultimately I think it was one of the weaker episodes. Episode 2 imo was the best, then 1, then 3 and 4 are tied in my eyes. I REALLY don't like the random zombie attack at the end and the "well, i guess im gonna turn into a zombie now so fuck it", it felt extremely contrived. The VERY end of the episode was bad ass though. This episode also brought to light how shitty the controls are sometimes. I'm playing on PC, and constantly having to walk around those school hallways and having Lee walk towards the fucking camera in the wrong direction against some lockers, it's difficult to explain exactly but I think PC players will get what I'm talking about. Again with the controls, I felt like the action scene in the bell tower when Lee falls through the stair kinda fucked up, instead of having a free range of aiming between your trapped leg and the zombies, it's relegated into two separate sections; so you have to drag the cursor all the way to the top of the screen, wait a sec till the game registers that, and then you can shoot a zombie or two.
EDIT: I say potential mystery because I felt like they try to play Molly as a mysterious person with bad intentions, or maybe even a Crawfford, but she just turns out to be a chick who wants to help her sister. That's fine as a character point, but it's dumb how she wanders off sometimes and you even see her run past the camera all sneakily like a few times, it's kind of annoying how that all just gets thrown out the window at the end. Not to mention that her mysteriousness was talked about alot in the episode, and trust played a major role in this episode in general, and then she just leaves at the end.