I observe that the core index.html file is only 13k big, but the game depends on two binary blob datafiles: “l” and “m” in the same directory, making the binary total size 22782 bytes (13,472 bytes in a .tar.xz file for the entire website with game).
It’s still impressive, but it’s a little bigger than 13Kib.
JS13k, the contest this game was made for, has the 13kb size limit for a ZIP containing all necessary files. The build process[3] produces a q1k3.zip[4] that sits at 13309 bytes.
Granted, the JS and assets without ZIP compression are a bit bigger, but when sent out over http with fast gzip compression there's still only around 15kb going through the wire.
[1] https://github.com/phoboslab/q1k3/blob/master/source/map.js
[2] https://github.com/phoboslab/q1k3/blob/master/source/model.j...