I know there is a randomize button, but there should be not a big red ball when you have not a red in one of the other circles. Also, make it a bit longer.
At first, I thought I had some time for beat a level (the numbers that appear at top left). Every level I said, wow, that was close. Then I noticed that was the circles left xD
Liked it. Way better than your other games. The easy mode wasn't hard, but to make it easier, I had to put my monitor's contrast to the max. Nice graphics too.