Better as a single film
I have no idea why Microsoft chose to release this episodically. There has been no end of complaints on this board about spoilers in the "next time" segments, as well as other issues that cropped up from the sporadic releases.
I watched the film's Blu-Ray cut with a halo fan who hadn't watched the show when it released as a series and he actually enjoyed it. Heck, I could imagine a lot of people enjoying this version a lot more. The pacing seemed tighter, it was harder to forget some tiny plot points that may have only been mentioned once, and there were no constant notifications about branching scenes, which in some cases had completely different tones than what was just on screen.
In short, if you really want to watch this movie (and yes, I'm calling it a movie), get the blu-ray version and don't even bother watching it on the Halo Channel (don't get me started on that, random quality drops and lock outs galore, now with added performance issues in the new version) It just begs the question why didn't Microsoft release the series as a film on the game disc?