When you first watch this, you probably won't like it. It's literaly absurd: the goal is to confuse and be incomprehensible. However, when you concentrate on the hard and the message of this movie rather than understanding the story... It can be pretty good! It's entertaining and makes you think about technology's limits and what is moral or not.
The story, as I said before, does not need to be understood completly. For the animation, as a Satoshi Kon movie, it's impressive, incredible and entertaining. The character designs are pretty much perfect! Plus, the music fit the different moods very well and the characters were fun to follow.
Overall, it's a good time when you get into its absudity. Enjoy the insanity and you will understand why Satoshi Kon's movies are so appreciated by the fans.