So, a few ideas thoughts on this.
I know my own computer setting might be causing some of these issues, but there is also some presentation and UI issues.
You made a fairly solid game, and seemed to really focus on it being hard and therefore good.
hard games can be good, if they feel fair to the player.
Since you have no formal tutorial, some people will feel intimated and try the mode labeled "easy" to try to get the swing of the game.
the "easy mode being an very well made homage to the Gameboy Mario games is really cool, but it would have been better as bonus, something unlocked maybe, because it's not visually engaging. You went to a lot of effort to make a version that is very visually engaging, but by lining the the modes up from left to right, how many people read, it visually gives a sense of progression. So, instead of playing the fully illustrated main game, people are going to try the unappealing "easy mode." considering the sensitivity of some of the hit boxes and how important the visual cue are to managing the controls, it's a very frustrating starting point.
Also upon dying the music cuts out, and will not restart until relaunched.
Also I think I saw the girl friend called "retarded" somewhere in the game, and that's just off putting and outdated language. I know people, especially in the gamer community through it around, kinda like "fag", but being edgy is not necessarily an enjoyable product.
What I am trying to say is you obvious have alot of very good ideas, but they all seem to be held back by a weird set gamer dogma's and it makes the game less enjoyable for people who just want to boot something up on a coffee break.
I know some of this worked well in the 90's and I love those platforms, and played the Game versions of Super Mario over and over, but in terms of what people are looking for from a flash game today, I don't think this is it. The punishments are too random and there just some hostile level design choices that it's clear are intentional.
I would like to see the some of the hit box issues worked out, and while there is totally a place for hard games, it doesn't feel like this game earns it, at it comes off to scornful, and simultaneously unpolished. I think got too attached to the idea of a "Hard Mario" and forgot the escalation of challenge is meaningful.
I like your art choices, sound design when it functioned, and you passion.
I would love to play the next version, or Weird Bunny Banana 2.
Thank you for making this.