Essential plot rundown: It starts out with apes, followed by some space stuff and ends with one of the greatest WTF moments ever put to film. So, needless to say, it's a very good film. However, it is not for everyone.
2001: A Space Odyssey runs about 2 and a half hours. But, unlike other movies of equal length, like The Avengers, A Space Odyssey is not packed full of action to keep the audience's attention. In fact, it is quite the opposite: slow moving with little going on. Out of the 141 minutes, there is only about 40 minutes of dialogue.
But, there is something about this film that is alluring. It has great visuals and it is intriguing to watch what is on screen. There are beautiful shots of spaceships floating in space, accompanied by classical music that make it feel like a ballet. With its minimal use of dialogue, A Space Odyssey is mainly a visual film. And the the visuals are strong enough to carry it.
The sound is well done too. From the score to the sound effects to complete silence, the use of sound here is amazing. It either adds intensity to the scene or grandeur to the image. And it seems like no sound is used in excess, only when needed. It is amazing how the imagery and sound can propel the film forward, even with its lack of dialogue and coherent plot.
The film seems, to me any way, largely metaphorical. There are no explanations given as to why different things happen in the film. (Though, I understand the book by Arthur C. Clarke actually gives explanations). With the movie, however, things happen and it is left up to the audience to decide what they mean. So, I'm not going to try to explain anything, because I don't understand whats going on. But, I will mention one brief thing. The film is divided into segments. The first one is called "The Dawn of Man" (or something) and is about monkeys. At first they are just hanging out, but then one picks up a bone and uses it to kill another monkey. So that's the dawn of man? Discovering how to kill each other with weapons? But thats just how I interpreted it and it made me a little sad inside.
But, overall, it's really interesting (and boring at the same time, oddly enough). The imagery is captivating. However, it runs for about 2 and a half hours and it feels that. So, because of it's slow pacing and unclear plot, A Space Odyssey is not for the average movie goer.
But that's just my opinion...