First of all, I love this game. It has the right balance of fun and challenge, and the graphics are pleasant. Since I'm motion-sensitive to vertical movement, I appreciate that the notes move horizontally instead; I can play it without feeling sick afterward. And the music selection is great!
Unfortunately, after playing for a very long time (over the course of several months, I believe), suddenly the game is no longer recognizing the progress I made. As you can see on my account, I've unlocked many medals. Now, all of my progress has disappeared. I did try accessing the game on my new tablet (no go; it wouldn't allow me to pull the keyboard up as an overlay in order to play). That's when I noticed that everything was gone. I figured it was a cookie issue or something and shrugged it off. But now that I'm back at the computer I've always used to play this game, I see that my progress is still gone. I haven't cleared flash cookies or anything of that sort, either.
I like the game enough to try starting over, but it's an absolute bummer that all of the time-related achievements and the ones I felt so close to getting are now in the very distant future.