Of every Visual Novel adaptation I have seen, this is by FAR the most faithful to the source. Every point that advances the plot, and every bit of character development, it is all in there. This unfortunately makes the scenes seem schizophrenic at times, jumping around in a way that is likely confusing if you are not familiar with the game itself. The music is good but they regrettably chose not to include any music from the original, not even remixes, and so some of the most epic songs simply aren't there. I left certain scenes feeling "This would have been much better if 'Emiya' hadbeen playing", if it isn't broken don't fix it.
The art is clean and crisp, and fitting of the style, and Nasu's amazing storytelling isn't absent either. (The only shame is the Realta-Nua parts, but that is to be expected I suppose.)
If you've played the game? This movie is a 10, if you haven't, it will sit at around 7-8.