Design Idea: Pacman labyrinth builder with player content 0 0

I know this is a problematic idea, yes, but hear me out:
This here is pretty cool (a 404 page with a little pixel canvas where visitors can paint and some user creations next to it): https://leftlogic.com/error

Now, what if I made this for the alakajam homepage but instead of painting an image you build a level for a vaguely Pacman-style game with ghosts and some destructible walls and a door thing you have to reach?
The player builds a level for other players to get out of.
You unlock new/more stuff to put into levels by beating other player's levels. The levels have tiers based on the number of things used in it.

Yes, the necessary backend is a problem and I have a couple of ideas about how to do it (feedback/other solutions would be very much appreciated!):

• no backend fallback: make the levels shareable via a link that contains the level data in some compressed base64 string
• put it on my server (alakajam admins might not be thrilled) and I'll just do what I want! Possibly make a version for Nextcloud after the jam.
• big version: fork the alakajam website and put it there so only registered users can create levels others can see (alakajam admins might not be thrilled) -> cooler for regulars and limits spam