The titular Game Child is a real device, released as a cheap knockoff of the GameBoy. They aren't as rare as depicted in the film, however. Shortly following the film's release, Stuart reviewed a real one.
The "sad onion" info-graphic appears several times during the opening credits, usually as enemy sprites in the games that Ashens sprite is playing.
Vinnie the Vole, a character from the fictional game "Vinnie the Vole's Existential Nightmare" that featured in an installment of Ashens' Tech Dump, also makes a cameo appearance in the opening credits.
A location named Sadonion in the film is named after an info-graphic that appears frequently on products reviewed by Ashens on his youtube channel that he's dubbed the "sad onion" due to its resemblance to an onion with a sad face on it.
The typeface used in the opening credits is the same as the one used in the original 1980s-era Atari logo.