I created a game inspired by Doom and the backrooms called The Backdooms under 2.4kb in minified html. (for reference, this entire post would be around 1.8kB haha) I had to use a not popular way of using GZip with Zlib headers (had to write my own script for compressing it, also in the repo) to eventually convert it a size 40 QR code that works right in your browser using Decompressionstream API.
This is of course a very oversimplified description of it, using a lot of the same technologies that DOOM had but combining it with infinite seed based map generation in 2.4kb (QR codes can only store 3kb, which includes changing formats) was pretty hard.
Here are some links about it if you want to nerd out and read more:
Repository Link (MIT License): https://github.com/Kuberwastaken/backdooms
A Hosted (slightly improved) version of The Backdooms: https://kuberwastaken.github.io/backdooms/
Game Trailer: https://www.youtube.com/shorts/QWPr10cAuGc
My Linkedin post about it: https://www.linkedin.com/feed/update/urn:li:activity:7295667...
(PS: You'd need something like https://qrscanner.org/ or something that can scan bigger QR codes and put the text data onto your browser to play it)
My Blogs documenting the process and development in detail:
https://kuberwastaken.github.io/blog/Projects/How-I-Managed-... https://kuberwastaken.github.io/blog/Projects/How-I-Managed-...
I have them credited in the repo as well :P