Make the ball bounce off, not stop. If you hit a wall, have the ball bounce off, dont have it stop rolling if you hit a "Wall" that is invisible.
alright so the concept isn't all that original and you've just turned pacman into > pacman without a face Ice version. except in this version the gameplay sux.. Really I played for 3 muinutes and I got stuck in walls, I fell into holes miles from where I was actually rolling(?) . Overall you got an already-seen-good-idea worked out in a lousy way