This was a good premise.
I liked the effort and the idea, very enjoyable, but I have a few gripes...
I think the gravity might have been too harsh... I understand that the sphere was heavy, but... it would go from a powerful forward roll to a straight downward drop.
I also think that there should have been some sort of penalty for missing the goal. Maybe three misses a level or you have to start the game all over? This would make the game a little more difficult, and therefore addicitng. Music would also have been nice.
Other than those gripes... it was amazing. The premise and devices used in the game were amazing. You truly did a great job.