its actually not that complicated at all,
first i made a texture pack that is fully greyscale (like no colors at ALL, absolutely zero)

texture without the color correction effect turned on

texture with the color correction effect turned on
then spent maybe a day or two messing around with color correction effects to basically “find” some specific values that will make all textures basically start semi corrupting because of the saturation, but the contrast evens out how absurdly blue the saturation will make everything,
this leaves us with a weird shader that makes all parts weirdly bright
and to combat that we have to limit the colors we can use to either greyscale colors, or colors ranging from RGB of 140,140,140 to 255,255,255, otherwise the parts turn into weirdly neon things
(i usually only use pink, cyan and blue for the entire game to keep the color palette consistent)
for example heres how the circus looks without the color correction effect turned on
and heres how it looks with it turned back on
the hot pink fabric parts are actually plainly grey, but our odd color correction effect makes them pink
a thing to note is that the fog matters a lot on the color saturation aswell, for whatever reason
and last, i put a forcefield part infront of the camera for the pulsating effect that you can see occasionally
(do not put glass parts infront of the camera or it will break all particles and billboard guis
theres probably more you can do with the simple idea of overtuning color correction effects to the extreme to achieve unique visuals, thats just my take on it
so in the end we get cool jpeg looking visuals at the cost of color variety
(also everything above applies to particles aswell)