Just downloaded it to give a try.
I had some problems with the accelerometer movement. Laying flat the marble moved up the screen. Perhaps a calibration problem with my unit, but running Tricorder shows all is ok with the accelerometers.
Also, the movement seemed a little stilted. The ball doesn't really seem to obey gravity all that well and has no inertia or momentum. Correcting the physics of the marble would do wonders for the "feel" of the game.
Enjoyed the levels I went through, and will do more.
Do you have a Droid? The ball stays still when I put my phone flat, I will note that there might be a problem though.
We wanted it to be controlled directly with the accelerometer and not have inertia and momentum involved because it would be more difficult to control. It could be an option in a future release...
Let me know how far you get, the first 10 levels are fairly easy.