I've played quite a few of these dice puzzle games now, so I didn't find the levels too challenging. The art on this one was nice and the music was calming - perfect for a puzzle game.
My only suggestion would be to remove the timer. A puzzle game like this doesn't need an additional challenge. For me it was quite annoying when I had solved one of the levels but ran out of time on the way to the goal.
In any case, great job on this!