Add a mushroom secret in the settings that makes everything look awful.
Or maybe add some other joke settings like in the language tab, there could be a secret language called "meow" that changes every word into "meow" or "MEOOOOW" (for OMG!)
#Goofy suggestion:
ornate hatch
pine zodiac
adding in something that makes the game look bad is counter-intuitive to wanting people to download your game
celest cobalt
I assume they mean like the visual settings in ultrakill?
I guess? It's already a pixel game, you cant do much
ornate hatch
Like make the screen rainbow and wavy, bruh
young pebble
... Maybe as an effect from a boss's attack?
pine zodiac
make a leprechaun boss and have that be it's primary attack