It is really well done. Seriously challenging. It has me pretty hooked at the moment. It is single player only, and not an action packed shooter, but it sure grabs you once you get in to it. Have a look at some of the reviews. Also, have a look at the youtube playthroughs, especially the ones by Scrapman. The couple that he has on there are super informative, and the guy is a serious actual rock climber, so his impressions of how the game works are legit. Also, his playthroughs don't, at least not yet, contain any serious spoilers. Don't do the complete playthroughs to the end, they will definitely reduce the game for you if you buy it.
If the game interests you after doing that, I would say jump on it. Good luck with it, if you leap, pm me and we can compare notes.