Haha was wondering if this'd be posted, I'm the guy who animated it together (my Twitter handle and username is at the end). I tried to make a playable demo in Game Maker but it was really hard to emulate the screen transitions, considering I've never really made anything in it before. So yeah, sadly it's not playable, though if any aspiring game devs wanna talk I'd be up for a collab.
I kinda went all-in thinking about how it'd work so feel free to shoot any questions my way.
The big question mark right off the bat for me is how would the Rune abilities and the many shrines which use them work in a 2D environment? They're all physics-based and heavily rely on the 3D environment to work properly. You could maybe salvage Cryosis and Stasis, but Magnesis stuff would just be gone.
Would probably require some major reworking of the puzzles and a lot of the game. Would be very interesting to see though.
With regards to this I decided only three rune abilities would be in the game, Magnesis, Stasis and Bomb. The latter is obvious, but the former two would basically be a way to move stuff, either through rudimentary physics or an extended hookshot. There'd also be much fewer shrines in my mind, considering the smaller map.