The animation
This is one of those films where the animation is so poorly made and distracting (psychedelic at times - on purpose of course) that it ruins the whole experience for me. It distracts me from the message the creator wants to convey and it made it really hard for me to get through it. I had to really push myself to see the whole thing. I like the message, it's beautiful and important. But the execution is so poor and sloppy.
I'm fine with the narration and the beautiful classical music, but imagine if Don chose a different kind of animation. I sort of like the fusion of real life footage and his doodles at the end of the film and I feel like he could easily have used that throughout the film (though less vibrant and colourful during Bills time of hardship and dispair, first half of the movie). Though a more refined, classic animation would be even better.
In a way it sort of reminds me of the animation in Waking Life (2001), where the animation is so wobbly/shaking and distracting that it makes it a really tough film to watch. It's so hard on the eyes and I found myself often looking away to just listen. Still a good movie though.
Wouldn't want to see either film if I had epilepsy.