Currently it's only available currently on the Amazon app store and costs around $5. RetroGamesCorp has a guide for installing and setting it up for those interested.

For those that have tried it out, do you happen to know if it lists whether achievements are available with a trophy icon like AmberELEC does?

The videos I've seen haven't shown it.

Edit: The app is longer available on the Amazon app store. They have shifted to Patreon. I made a follow up post about it with their explanation which can be found here in !sbcgaming@lemmy.ml