Indeed, many of them appeared to have been either put together from clip-art by a four-year old, or scrawled in crayon by a smelly GCSE art student, or someone who got a cheap airbrush for Christmas.
However, the same thing could be said of the musical world too; for every Unknown Pleasures or The Velvet Underground & Nico, there's a... well, there's a load like these - which appear to fall in the intersection of the Venn diagram of covers that would work just as well for old games as they would for terrible albums.
Behold this thing of which I speak!
Anyhow - here we are clearly looking at the cover for a late-80s point-and-click fantasy adventure game. Magnum, you bunch of melts! (The ice-cream-called-Magnum joke).
"Hi, guys! We're really slippery."
"How do you like the game you're in, sir?"
Also, she looks like she's about to administer an enema.
Sierra Online's Legends Of Enema: The Brown Crown.
Also: can you remember the trick daddies you used to be able to get from the practical joke rack at the corner shop? You'd take them round your friend's house and lay them in the hall, and your friend would think it was their real daddy, and that he had died.