Thanks, yes I'm the dev, so don't hesitate if you have some suggestions or recommandations for improve the app. (I will create a thread when I'll reach the post's count to 10)
The app was developed for WP 8.1 but I have arrange it for W10M and it's working like a charm.
I've tried out your app, and while the app is really really fast (job well done on that!), I just didn't really like the UI I dislike the UI simply because it didn't really match W10M's design language (the fonts, the buttons, they all remind me of WP8.1, and after using W10M, I've simply grown to dislike WP8.1's design language).
Also, I'm not sure if it's just me, but I guess your app doesn't have a 'Now Playing' feature, isit? Because when I play a song while in the app, the current song playing is only shown at the bottom part of my screen, and tapping it doesn't take me anywhere. So basically, since I'm a fan of album artwork, I really found it surprising that there weren't any proper "Now Playing" screen, but I guess you'd have to omit some features to get that blazing fast performance, right?
Also, the ability to play FLAC is a really good addition, so good job dev!
All in all, I liked your app for it's outstanding performance and the simplicity of it, but tbh, your current app is just not for me (at least not yet), simply because of what I've said above. But since the official update to W10M is just around the corner, I really do hope that you would try to update the app, and add extra features. My suggestion is (based entirely on MY preference):
1) Provide a proper 'Now Playing' screen
, that displays the album art, and also a properly-sized toggle to drag the song's current time position, or whatever you call that thing, because in your current app, the slider is really small, and I accidentally pressed the pause button a few times before I manage to skip parts of the song.
2) Provide more interface customization!
I really like how you allow the user to choose the theme colour, but as it is in W10M, there are waaaay more accent colour option that in WP8.1, so I guess you can add more? Also, allow the users the option to use our phone's accent colour , and also maybe provide some different themes for the music player (like what Loco Music provides).
3) Automatic/Manual Editing of Metadata Tags!
Well, this feature is provided in Extreme Music, and that app was good in WP8.1 (not so in W10M). I guarantee that people would love this feature on their music player.
4) Additional features?
Okay this is just me being greedy, but yeah. Maybe you can try to implement some neat features like Last.FM scrobbling, auto album art downloads, artist background etc.
P/S: I'm sorry if my feedback may not be what you wanted to hear, but that's really my honest opinion. Also, what I've suggested above are just based on my preferences, as well as based on the other music apps I've used. I do hope you can make your app better, as I really love it's performance. I look forward to your app's next major update!