In reply to Adders:
Like jonzza, I grabbed a copy of _Insurmountable_ when it was going for free on Steam. It's more a mountaineering game than a climbing one : the challenge is in route finding and managing your limited resources to keep your climber on the move - energy, internal temp, oxygen (at higher altitudes), and sanity (not going off the rails from being alone and in permanent danger for so long). The climbing is simply a way for your climber to get about, no more exciting than the walking (though, TBF, running out a vertical section against rapidly dropping energy is kind of tense!).
I'm looking froward to _A Highland Song_ : though, again, the climbing looks just to be a way of getting around a platforme, in manner of early Lara Croft (holds either are perfect or totally unusable), the environment looks like it'll be very pretty (and, since the developers are from Scotland, might even look like the Highlands rather than Generic Hilly Wilderness #412)
_Celeste_ is wonderful and fun but the mountain's more there as a metaphor. I love playing it but climbing it is not!