With a touch of Minecraft to boot -- but only if you squint.
In Lemma, you play as a physics grad student whose colleague gets lost while exploring an alternate dimension called... Lemma. Communicating with him through texts, you cross through into this other dimension to help him out.
What's special about Lemma is that, well, basically, the walls are made of magic. There are red walls and platforms that hurt you, blue ones that help you, and as you run, climb, jump, and otherwise free-run through the environment, you can extend walls or create new platforms to get from point to point. There's a minute or so of footage demonstrating all that in the Kickstarter pitch video below:
As the project page explains, the game's main mechanic was actually inspired by Minecraft; frustrated by how bland the act of creation was in Minecraft, where you simply click and a block appears, the creator tried to make a game where building required the act of movement instead -- hence your parkour extending walls and summoning platforms.
It's a really fun-looking exploration puzzler, with a lonely, Portal-esque atmosphere. The Kickstarter campaign itself has a very humble goal of $US10,000 -- $US10 for the full game, which promises three hours of gameplay for the first playthrough. And by the looks of it, just like Portal, this game is definitely worth multiple playthroughs.