Solid concept and fun physics! I think an enhancement would be to have a different shape forbthe cursor, like a scoop or something, to really push what you can do with the physics.
I thought about that as well. Scoops, rotating squares or just bars. Also, the left and right zones could move or be temporarily partially be blocked. The whole concept could work also in a spherical environment etc. A lot of nice things that can be added :)
