[MikusR]

Are there people who have managed to watch this movie in one sitting without falling asleep?

[p_l]

Yes. I was captivated the first time I watched it, many years after watching 2010.

However, if I watched it on a plane, I'd probably fall asleep as well - because it would be on a plane and I tend to sleep while I travel :)

[Koshkin]

As with some other movies, this critically depends on how you watch it. Immersion is key here, so you must watch it on a large screen, in high resolution (and definitely in one sitting).