This demo sucks!
Haha just kidding!
Its interesting though, what makes it slow down is lots of draw, an issue with the canvas. When i look more top down at it, it rotates fast, but from a more side view, its slow.
It lends some possibilities to the raycasting demo from before, that if you can minimize the drawing the canvas must do, by using the bitmap renderer instead, you could get some good speed from it.
Perhaps if you had texture sets, with all the sizes,....i mean, in wolfenstein, the walls only rotate on the x/z axis, but never the y axis.(i'm calling x the angle rotation and z is the depth(zoom) of the object). If someone can put all these puzzle pieces together, i'm sure there's a way to make a fast 3d program with no need for gpu.
Basically, take Feral's 3d examples which ran fast,combined with yours which are more convincing....perhaps it can be done!