SubFire Player is now up to version 0.7.5 - the 'beta' is officially released on FireOS and Chrome with full folder browsing mode instead of only supporting a basic shuffle.
Clicking the play icon and/or the play/pause button on the remote will play all songs below that point, just like the Android app does. It also tries to be smart about remembering the last selected item as you back-button back to the folders page.
There's no 'queuing' mode yet. I'm still thinking about how to approach that with an eye for supporting the new queue API in 5.2 without depending on it. Also in the idea queue as I head for the 1.0 is shuffling the current play queue, viewing the queue itself (as a list to help skipping to a new track), album-browsing (similar to the main web app's front page), and browsing by ID3 tags (artist and/or genre).
As for Android, Amazon's kinda (finally) making it clear they won't release it for non-Amazon devices anymore (this is a policy change in general, not specific to my app - if I wanted to ensure it could be released on other devices, I'd need to change it to an APK upload instead of just the html5 zip content, which also means I lose version history (and existing customers would need to 'buy' the new version separately and uninstall the old and that's just too damn tedious). Oh well.
I'm now trying to decide if I want to pursue another app store (Google Play, or perhaps Samsung) or just leave it where it is, use the APK just on my own boxes. I'm sure given that it is oriented to TV sets that there may be interest in it on Android TV and/or Samsung's smart TV's, but I'm in no position to test those and deal with the differing remote controls. So really, if I push on Android it is for these other TV tools rather than to 'compete' with the other apps already on the Google Play store. Those are all really good for phones and tablets, just not optimized for use on a TV with only a simple remote control as your input. In the same vein, since my app uses pure html5 audio tag with limited caching/buffering, it doesn't work terribly well with low bandwidth phone networks, so there we are. Right tool for the right environment.
http://www.subfireplayer.net/