This was a standout game amongst the rest for me. Super simple concept and nicely polished. Keeping it simple is always a good point in my book. If I had one critisism it would be in the controls. Consider placing the jump action to the mouse button as well to give people the choice of how to navigate.
Would also consider leading up to the harder section a little later in the level to allow people to really get into the controls before putting real obstacles in front of the player. Other than that, really very nice and lovely looking visuals.
This reminded me of a cross between Super Monkey Ball ande Marble Madness. Good job!