All the Getter energy attacks have properties that match various energy/radiation weapon types. Getter Beams tend to behave like particle beam sprays or laser-like streams of Getter rays depending on the concentration/charge of the Beam, and the Stoner Sunshine evokes a controlled thermonuclear reaction of Getter energy, which can generate sufficient physical pressure to rip Metalbeast Dragon(an augmented version of the mass-production Getter Gs)'s armored skin clean off its endoskeletal frame. The effects also extend to how direct exposure to the Getter Rays is lethal to several of the villains - Dinosaurs melt on exposure, and the Invaders in Armageddon "over-evolve" and self-destruct in a manner akin to radiation sickness and/or cancer.
Speaking of endoskeletal frames, many, many shots of the Getter Robo mecha without their "skin" of metal plating tend to expose a massive and extensive system of mechanical muscles. For the most part, this explains the terrifying physical strength of the Getters when they have power to spare.
Many combat damage closeups tend to show that the Getter's external plating is but a thin layer of metal plates, and several closeups of the Getter Robos in Armageddon show that the skin can be generated spontaneously as part of the combination sequence. This explains how the Getter Machines can morph easily between forms with an organic smoothness not seen in many other Super Robots - Its "skin" of metal panels is clearly very flexible and capable of rearranging itself neatly. It also explains why the Getter is a bit of a Glass Cannon compared to heavily-armored titans like Mazinger Z and the GaoGaiGar, which have solid bodies made out of whole cast-chunks of heavy armor-grade alloy. Furthermore, this means the Getters can just spawn their weapons just by making them out of the same plates formed into weapons.
In the Armageddon series, there's a scene where Go kidnaps Kei and starts some sort genetic exchange inside of Shin Dragon. As creepy as this sounds, there's a reason. Go was originally part of a set of three genetically augmented people, before the other two mutated. Later on, we see that Go needed Gai and Kei to finally get Shin Dragon working properly, and the process nearly killed him. He was trying to augment Kei so they can get Shin Dragon running.
In the Arc series, Baku Yamagishi is shown to have mild prophetic abilities tied to the Getter Rays, along with his brother Messiah Tahir who had superior powers. This sounds freakishly occult and out of place until the reveal that in universes where the Getter Emperor exists, it has become a singularity unifying the universe, thus changing how time and space work (contrary to Kamui's supposition that changing the past would branch into a new reality and not fix the future). By reading between the lines, you realize that since Getter Emperor is fated to be born or at the very least carries the possibility (since Andromeda Country attacks Earth in the past), the brothers' prophecies come from feedback provided by the Getter Rays, as they merely nudge them in the right direction for the birth of the Emperor and humanity's universal domination.
Before being adopted by monks, Benkei Musashibo was living in the wild, stealing food and kidnapping girls from nearby villages. Now think what he needed the girls for...
