I think the "Ugh, nobody could watch this, it just gives people a headache" argument died with MTV.
This avant-garde approach to film-making certainly isn't popular, even among cineastes who take film seriously. However, it's still an effective film, even if neither hide nor hair could truly be reaped from it. It tends to annoy people when something isn't supposed to make sense (even when it follows a narrative like 2001: A Space Odyssey), but it's not ABOUT making sense much less than it TRIES NOT to make sense.
You're supposed to sit back and watch, and that's all the work you do. If you can't handle that, then I'm confused as to what you get out of film.
But enough about you, let's talk about this movie. According to Brakhage, it's supposed to tire your eyes, make them exercise, work them "to see with one's own eyes", to relearn how to see, all that wonderful philosophical stuff. However, jabbingly quick editing and barely synthesized flashes of color are actually the mainstream of cinema now (think stuff like Domino), thus that appeal is quickly lowering. Instead, it's becoming... *gasp!* relaxing! to watch this film. It helps that this, the prelude, has no sound. Instead it's just a flow of flashes, a realm of color easy to get lost in.
--PolarisDiB