Your fear is warranted, comrade

It's a very quick and dirty solution as I suspect dynamically creating a 2D collider, or generating a custom mesh a la Minecraft, would be a lot more performant (neither of which I had the time to research and implement how to do for a game jam). Essentially there's an invisible wall with a custom shader that's basically unlit yet can receive shadows. I generate two render textures based on this (one for each wall). When the game is started, it generates 88x42 cubes (that's what the loading bar represents: the generation of these cubes). Then each time you move a cube it reads each pixel in the render textures and either turns on or off a cube at a corresponding location in the world.  Finally I do another render texture of these cubes and use that texture as a second material for the visible walls in the game. Just gotta make sure everything on that second render texture is pure black and you'll have what appear to be shadows on a wall that can be fully interacted with.

Edit: Also glad you like my crappy Russian accent, lol

Thanks for the feedback! Yeah I honestly keep going back to it myself to find unique solutions to the harder levels. I'm considering looking into optimizing the interactive shadows (as they're currently only performant at a super low resolution of 88x42 pixels) and seeing about expanding it into a full game.

Da! Have a vodka on us, comrade!

It's basically a platformer but you aren't the one platforming: an AI is (in this case just a dumb AI that walks back and forth and sometimes jumps).

Edit in case this is still confusing: the Jam's theme is 'collaborate with AI'. In the truest sense of that phrase, that's what you're doing in this game. You are effectively building the platforms that, essentially, a Goomba from Super Mario Bros needs to navigate to get towards the end. If you don't build the platforms, the goomba either dies or is stuck in limbo. And you cannot directly control how the goomba moves for it is a goomba and only knows how to moves back and forth (and sometimes jump because these are slightly more evolved goomba).