Great game, very polished, but it looks like there's some kind of graphic glitch. After clearing 3 or 4 blocks, the top left Menu/Back button/area starts changing colors. Here's a screenshot: http://ompldr.org/vaGF3bA
I thought of it as a glitch too.. till I made enough progress in the game to find that it was a progress bar. Would be better if it started from the right of the 'up' button and not from the very edge of the screen.
