I can't say I like how the game controls. The hitboxes are wonky, there's a weird lag when you have over a certain number of plumbers on screen at the same time, not to mention some very mean medals that take a little more dexterity than I would like in a casual flash game. It has charm and a nice subversion to the traditional Mario platforming tropes, but I wish it played better.
The game is not difficult; however, there is an issue. That you simply did not put into the game. It's called "Variable Jump Height." You know how when you jump in most games, you can control your jump? That's what your game doesn't have. It makes your achievement difficult to do survival.