: In the final chapters the parts where you grab jet packs to board the Lich
: and try to escape while gravity goes haywire are some of my favorite Halo
: moments including all the campaigns. It's a shame they didn't have more
: time to polish up the front half because it's clear they took feedback to
: heart as made far more dynamic encounters after the hiatus.

I'm pretty sure they made all of the content before the game was released and just put it out one episode/chapter at a time (I forget which one it was)-- there was a whole big discussion here about how they couldn't have gotten much done in the course of a week or two or even a month or a month and a half, especially regarding some of the material that went into the pre-rendered stuff.
Anyway, the gravity thing was interesting, and so was the Lich fight you mentioned. The beginning of... I want to say chapter 7... was actually challenging, although that was because of an added failure condition. I'm pretty sure there was more that I liked that showed up in the second half of the season but it's not coming to me.