Shaun_Max web works in the beta channel but it is not really refined or "production" ready. All the apps I tried, seem to work ok, but there are a few things off, like taking too long to load (might need a preload or something). I might be able to release the app in web too, in order to be a reference for that. Also some packages (the equivalent of ANEs) only support Android and iOS, not web, so you would need another package to replace the mobile ones.
Concerning games, I have used flutter to work on small "form" based games, like a quiz game, a decision based story game, but I wouldn't go above it. Reactive programming for gaming feels 100% off, as on every change in the ui, you have to rebuild the whole ui.
For 2d games I use other alternatives which are very good on what they do and easy to adapt and use.
Thank you for spending the time to check the article 😀 I hope it shed some light.
Edit: I also added a link to the "web app" target. TEDxAthens2016 web