Good!
I really enjoyed this. The game concept is a familiar one but the countdown balls add an interesting twist! They kept forcing me to make panicked tactical moves too try and group them with balls of the same colour. The music is a good choice too.
Ideas if you make a sequel:
-Give a bonus if the player clears all the balls in a level.
-Additional powerups to help you battle the countdown balls. Sometimes it's really tough to group them fast enough so it would be good if you could save a powerup (such as pressing space to temporarily freeze all counters) for such an occasion :)
Anyway, nice game I hope to see more from you ;)