The easiest way to explain is with a video. Jump to 0:17.
The view is warped in a circle that expands away from its centre. Can this be done in Unity Free? If so, how?
Here’s a still:
Cheers
No. You usually need RenderTargets for that.
In theory you could create vertex shaders for your level geometry which distorts geometry relative to screen-space, but that will get messy soon 