In Light Is Waiting, the very first thing we notice is how dated the footage looks — this is accomplished with digital effects (presumably). On cathode ray televisions, the picture was formed by an electron gun that traced lines across the television screen faster than the human eye can see. This causes small lines to appear on the screen when there is a lot of motion, which can be approximated with a digital raster effect (this is what we see here.)
A more extreme version of this, with a flickering effect, is then scene when the TV is dropped in the next scene.
From here, we see a quick succession of extreme digital effects applied to give the impression of a dreamlike, hallucinatory sequence. A man jumping from the top of a waterfall is shown in a mirror effect, with the screen reflected across the center.
Two scenes, one with the opacity lowered, are superimposed on one another, giving the impression of ghostly trees hovering out of view.
Red, blue, and green (these are the component colors of a CRT television’s picture) tints are applied to some scenes, flipping back and forth rapidly.
In total, the digital effects used here serve the overarching feel of the short, summoning the nostalgia inherent to the VHS/CRT era and infusing it with a psychedelic, unsettling undertone.