I liked this Flash game for a couple of reasons.
The first reason I really enjoyed this is because... it's a game about a marble venturing through levels collecting coins and avoiding obstacles and so on... And somehow you managed to give this game a PLOT. LOL!!! That is awesome that you are clever enough to tie a plot into a game like this.
The second reason I liked this game is because of the overall design. Like Lordmoocow said, I also believe the art and animation could have been a little cleaner and more detailed - but he also hit the nail on the head when he said it's obvious you worked hard on this.
The scripting is near perfect, the interactivity is good. You threw in plenty of obstacles and changed things up well. The playability is good, it could be a little more fun - it gets a little boring but there isn't much you can do about that.
Feature wise, the only thing I could suggest is that you add a main menu, which tends to be a good idea for any Flash - especially games. It offers you a chance to put in a tutorial, credits, a 'quality' selector, a level selector, and many other things. Also, you could add easter eggs, if you didn't. Secrets tend to keep a user playing for longer, in hopes they'll discover your hidden treasures.
And as an aside, you preloader was kinda neat with the interactive gear... thing.
That's about it. Keep working - you are a good animator and and even better programmer.
- 3/5 -