I like the little Marioésque experience you’ve whipped up here. The style and feel is quite enjoyable, and as many have said, it makes you yearn for more content.
The parody-element leaves your imagination running on what other “Mario-tropes” you could tackle here. Someone already mentioned real stinky sewers.
My first thought would be a turtle, and if you’d jump on the poor thing Mav would be rightly accused of animal-abuse.
BTW, I noticed you could jump quite high (and even through the ground) if you manage to mash the controls accordingly.
It was also possible to kill this fellow on the second run (even though he was supposed to beat you “this time”).
(I find it always fun trying to find this kind of “loopholes” whenever possible)
But all in all good job! Cheers!