Why do the credits say "April Fools"? I know it's April 1 today, but what's the prank?
I'm assuming because it's a parody of Dr Mario?
I think it's just the joke is just Annalynn being a doctor and not a miner. I know on socials it was made a bigger deal of her retiring from mining and taking on the new career. If anything, that's probably what the joke is.
The prank is that it's not a platformer, usually indie devs will make a game that's not their usual things on April Fool's and make them playable.