There's something in this idea. you can actually tie it to a smart watch (Amazfit allow for custom apps trivially for such uses), and you have a bigger pool.

Thanks, yes, I agree - it really doesn't "feel like" exercise when you're being bombarded by dopamine rewards. Despite this, most "exercise games" leave me with the same feeling of boredom / "fake fun" I got from playing educational games on the computers in the IT room at school.

I'd love to try a similar approach to gamifying exercise on a smart watch. That's an even more fun problem, because (when running, for example) you don't even have a constantly-present screen to communicate dopamine to the player with. Perhaps some watches wouldn't even be able to provide sound feedback? I've never owned one. It's a really interesting constraint for game design.