Pros.
So first, it's not the worst thing I've ever seen I guess? The aesthetic was interesting in that it used two different styles for real and game worlds. The animation on the faces was fluid and detailed, especially on Kite.
There were also a few fun moments when Sora starts playing the game and learns the controls.
Cons.
So now the bad stuff.
The biggest issue is that this movie feels incredibly far removed from the rest of the series. Sure, there's the callback character designs to Kite, Balmung and Orca, Aura's in it and they play the "note" twice, but there isn't much tying this entry to the rest of the franchise.
Everyone seems to have forgotten the events of G.U. and the original games despite the incidents making headline news at the time.
No one recognized the Kite model (which is kind of hinted at to maybe actually be Kite, since it's male despite having a female playe, premade, and named Kite but that doesn't go anywhere).
They don't even seem to be playing the same game anymore (I know it's a different version of the World technically, but R2 kept a lot of the same classes and some of the areas from the first version). The big finale is an airship battle that looks like a cutscene from Final Fantasy XII.
This movie basically tried to turn .hack// into a slice of life, shoujo story that kind involves MMORPGs, which theoretically could be good, but it's not even done well here.
What made the .hack// series good was always how the various anime and games explored the reasons people played games, whether it's to escape from reality, make friends, kill time, etc. No other franchise ever looks at gaming and "gamers" the way .hack// did or has since and that made it unique for me.
There is none of that here in this movie though. It feels as if someone unfamiliar with the franchise took a couple recognizable parts from earlier entires, threw them haphazardly into a safe, feel good plot. It's just lacking in all the key areas.
