It's like running up the down escalator.
Your getting so close to clearing a colour. I need a red, just 1 red, it doesn't come and then bam, another row pops down. Even when I'm down to 2 colours, it's mostly based on luck if you can clear a colour or not depending on what spawns on top.
For some reason you don't spawn any specials, which would be nice to have a bomb come down giving a chance to blow up the tree stump but you only have them in the first 5 minuets. It's not until I clear a level and start the next that I remember there actually is other things besides colour balls.
Oh, and the points system is backwards. Someone that is very skilled or very lucky will clear the level very fast, not popping many balls and will have a low score. Someone that spends 3 hours trying to clear a level that just manages to stay alive will have a very high score when they finally do get lucky and clear the stage. Maybe points can start at 10,000 and you lose 5 points for every shot fired and gain 1 points for every bubble burst or something like that. Basically the longer you play the lower you score should be.