I don't know if I'm remembering this correctly but there used to be a site called html5lemmings (or something similar) where you could play a few levels of the game. This was before modern web applications and things were still mostly server side rendered with minimal javascript. The demo was quite impressive. I don't know if it's still there. Couldn't find it with a quick search.

dhtml lemmings

https://www.elizium.nu/scripts/lemmings/