I might be a bit of a casual player, so I couldn't beat it. The green circle of death would whittle my precious time, and my opponent would usually solve things in 2-3 seconds. Anyways... the predict the next one in the sequence was a bit confusing, the circle could - for instance - save the progress one makes (if the player got one right, they could just get 2 little bars in the retry and so on), and as suggested before the opponent could get the same game, so it could be more fair. Also the largest to smallest sequence takes too much time considering the other minigames.
Regardless the art is pretty nice and the visuals are clear.