Watched episode 0. It was basically the entire prologue from the VN, although much shorter in terms of the time it takes to get from one end to the other. It's very loyal to the source material, which is nice, although I hope things speed up soon because, having already read the VN's prologue I already knew everything that was going to happen in this episode (it's just that true-to-text). At the very least it does things in an interesting way and isn't as long-winded as the VN. The fight scenes have been changed slightly and are much better than reading through them, too.
They seem to have decided to give Saegusa bright orange/auburn hair this time around, but that's about the only notable change.
Music is good, and ufotable's visuals don't disappoint. I think I'm going to enjoy this one.
I always thought I might be bad
Now I know that it's true
Because I think you're so good
And I'm nothing like you