Nothing shows that this is actually running on bare metal. There's no description of how it was made, how is it connected, what technical limitations you had to work against or anything else that would make this interesting. The page itself is the only artifact.
10 minutes ago it was working. Now I get a Cloudflare bad gateway error. To me this is indicative of truth to the claim that the page might be running on a microcontroller or other weak machine :) But the page itself never mentioned if the HTML, CSS and JS is actually served from the ESP32-S31 or not. Or if the only traffic to the microcontroller was the “pokes” being sent by clicking the button on the page.