Whe it was first aired in NY in 1968, it was a disaster.......
But several days later, critics changed their mind and it gradually became an experience.
I've got Agel's "the making of 2001" and it appears those who loved the movie most were boys between 10 and 14 (I was 11 in october 1968).
I remember not minding the fact it was difficult to understand, but it was a new "experience". Apparently, girls and adults need to understand a movie in order to appreciate it.
I read the book after having seen the movie twice and it made me love the movie even more.
I must admit though, that after the real year 2001 had passed, I haven't seen it much.

Raoul