Looks like those sizes could be improved significantly, as the builds include names etc. I would suggest linking with

emcc -O3

(and maybe even adding --closure 1 )

edit: actually the QuickJS playground looks already optimized - just the MicroQuickJS one could be improved.

Nice. Got it down from 229KB to 148KB! Thanks for the tips.

https://github.com/simonw/research/pull/5

Thats now live on https://tools.simonwillison.net/microquickjs