First, I'd like to share some advise. It is good to introduce yourself in the
intro thread and to read
Feedback Forum Guidelines. Also, the more you explore TIGForums, get involved, and provide feedback on other games, the more likely you'll been taken more seriously and receive more feedback.
As for the game, I tried the Windows version, and the multiplatform release is a plus. I liked the simple visuals, since they fit my tastes and work well with viewing from different angles. I liked your choice of music (it would be nice to have a link to the musician). Also, the tutorial was helpful, but using "today we will..." in the text didn't seem like the best choice.
I wish there was an option to reverse the rotation control, since I feel it more natural for a cube to rotate in the direction I'm moving it. The versed-axis control felt awkward.
Whatever you're doing with the graphics settings in Java is being very friendly with Firefox running in the background. I had to keep restarting my browser after exiting the game to get it to display properly. It was also a big turn-off.
Good luck with refining qb.