This had the makings of a great climbing movie, then they did some stupid, unlikely things in terms of climbing (eg, the multipitch rappel, why not stop at the tree? (Wouldn't have made any difference in terms of the plot, but rapping to an obscure point in the middle of a cliff where you may or may not get to a ledge, without knots in the bottom of the rope, is, like, three mistakes rolled into one.)
Then the story leaves the mountains for the river and becomes much less interesting.
I see some reviewers are greatly bothered by who lives and who dies, and what was the point of everything that was done and happened; it's certainly not a standard Hollywood storyline, and I thought that was great. Some real surprises there. But I would have loved this story a lot more if it had stayed a rock climbing/mountaineering movie (and if it had done that better).