Disappearing Room Glitch

Though extremely rare, (on zen mode and possibly on only some devices) the Disappearing Room glitch can occur at any time.

Description
Although it is extremely rare, the door can sometimes appear blank before the disappearing room glitch occurs. The next stage you enter will not have anything visual, except the balls you throw, powerups, shadows, the door outline, and the gradient, there is also a blank door at the end.

After passing this stage, the next stage might consist of nothing. No solid surfaces, no objects, no music... just the endless abyss of echoing after throwing a ball, and a white background.