There's no UI in Cairn to tell me I'm in trouble, but I can see it in the way my protagonist, Aava, is shaking. Her knees are wobbling, and I'm high enough up that I'm really starting to wish I'd wedged a piton into the rock. It's going to be a long way down. 

Cairn, announced during the summer showcases and due for release next year, didn't wow me with its trailer, but it's sure wowing me now. Developer The Game Bakers, best known for hits Furi and Haven, seem to have struck gold here with a climbing game that makes it actually feel like you're climbing, something I've been eager to see for the longest time.

Climbing tall things in games is a form of escapism I've always vibed with, perhaps due to the fact I'm terrified to be more than about a meter off the ground at any point. Unfortunately, while games like Assassin's Creed and Mirror's Edge let you rocket around at impossible heights, leaping from structure to structure, it doesn't actually feel much like climbing. Hold a button to move or tap a button to leap at the right time and you'll parkour like a superstar. 

Cairn's climbing is a laborious process, with each limb available to be manually positioned. As a result, it's a crunchy and tactile climbing experience that you'll feel every second of. Tap a button and your limb will start to move, put it in position and tap again and you'll move to another limb. There's inevitably some bad technique to start—legs tucked into each other, arms crossing over—but over time you get into the flow of climbing in Cairn and the game sings. You'll have to move fast, as holding a bad position for a few seconds too long will send you tumbling back down to earth. 

Climbing then is a mix of eyeballing a route and then also quickly trying to tailor your technique as your ascent plan disintegrates upon contact with your rocky foe. Shimmying across a ledge because the angle you thought would work hasn't panned out, or taking a more complicated path because you just can't see a way forward.

There's a story, but I'm not shown much of that during my brief hands-on. That's fine, because as soon as I get through a brief climbing gym to teach me the basics, I'm cut loose to climb an entire mountain. The whole thing is climbable, I'm told, and it's entirely hand-crafted too. You can see that there's not just a human touch but that of a climber in the routes, as several are simple enough to be daubed with yellow paint and sent to live in an Ubisoft open-worlder, while others only become apparent as you climb them, sweaty palms gripping the controller as you realise you've bitten off more than you can chew. 

I only played for 20 minutes, but Cairn was probably the most exciting game I played at Gamescom this year. There are other things here: That story supposedly involves a bigger mystery, and there are some other mechanics in play, including the ability to force pitons into the rock and have that rope retrieved by a cutesy little robot. Really though, I'm just here for the climbing. If summiting the mountain in Cairn's full release feels as good as this brief playtest, then this is going to be an essential game for those who love to climb, and another example of an indie game with a core central mechanic that makes it agonisingly compelling.