I'm almost done with the book, but I know what was "cut", and what wasn't so far. The first book starts at episode 8, flashes back to episode 1 and eventually flashes to part of episode 3. Episodes 2,4,5,6,11,12 are absent, they should be in book two. I am at episode 13's events right now and it rolls right into 14/15 based on my quick glance ahead.
A few additional sections are added, including something I thought was a joke... but is cannon.
Lots of added details that the anime gloss over really help to explain a few things, so this is a very worthy read so far.