It's because the contrast is shit. The backgrounds are the same saturation as the sprites and there's no border around them to compensate. Take a look at any good sprite game.
Notice how, even with a detailed background, the characters aren't lost in it.
Same here, and I specifically found a yoshi on a green background to show how much color theory can help. Not only is there a black outline around the characters, yoshi is still a different hue than the background so he doesn't get lost in it.
If anything, the gamegrumps prove time and time again you can do anything even without any sort of talent or knowledge.