You won't believe this: it _is_ playable on mobile! I see a lot of people playing this on their phones and iPads.

I contemplated adding gyro controls, like in "Marble Blast Mobile" from back in the day, but they are very imprecise and don't really scale well to high-level play. With the current d-pad controls, there's actually a mobile player who holds the world record on many levels. Never would've expected mobile controls to scale this far.