this is extremely cool !! i love that there is kind of a creative challenge where the player has to break rules that they themselves have come up with (or rules inferred from their knowledge of how super mario games work) , or just make new rules, like imagine a new power-up for example (on my second run, i imagined mario had a pickaxe to break blocks).
In my opinion this game works a lot better than the original "8 - imagine" from "What is a video game ?", probably because of the sequential nature of it, but also because the image is static so there's more room for interpretation of the koopas' animations, and there's no music so you can imagine any music, or even go on youtube and search for one to play in the background lol.
Although, i think the game quickly loses momentum once the setting completely disappears imo. Once the clouds were gone, i was thrown out the game completely lol
this makes me think of when i was a kid, i would draw platforming levels and parkour challenges for characters to go through. i would either imagine the characters moving or draw a line that would represent their trajectory.
i could see multiple players playing the game at once, and after each level, they would talk about their solution to the level, what they imagined the characters did etc. but maybe it would be too bothersome to explain with words some actions that seem so straightforward in imagination... mmmh...
anyway, all of that to say, this is a very very cool experiment, and a great source of inspiration !