How the hex do they do a fullscreen x-dister on a regular ST? It should be impossible, so it's sensible to suspect a trick. One idea that came to my mind was that there is no actual bitmap distortion going on, but instead the effect is based on color palette modifications using 12 cycle move instructions. One clue to that is that is the observation that all the disting fullscreen graphics are zoomed, i.e. really big, with about 41 "pixels" per scan line.
But then the question arises: How can the timing of the color changes be delayed with 1 pixel precision (at least that's what it looks like from inspecting a frame from the youtube capture)? Is there some new Shifter/GLUE trick that can distorts video timing in a way that the location of a palette switch is shifted? Is it related to Alien/ST-Cnx' 4-bit hardscroll trick?
Either way, my hat is off to you, Troed! Congratulations from an amazed old school scener. Achievement unlocked!

Gunnar
(Big Alec/ Delta Force)