I think this game's difficulty is the thing everyone knows. It's the "borderline impossible Mario game that is only for the truest of gamers". The thing is, this game really isn't that hard. It just takes practice, and the game thankfully has a much more generous continue system than the first, allowing you to continue from the beginning of a world. A lot of this game relies on simply being able to make precise jumps. Can you position Mario accurately enough to land on a single block? Can you get a perfect running start and time it so you bounce off the Paratroopa and get enough height? The game's difficulty can be annoying but oftentimes it leads to experimentation. Each action you take in this game needs to be incredibly thought out ahead of time but the game always keeps you on your toes. It's the same feeling you get from other difficult platformers. In fact, I'd say nothing in this game is harder than a lot of modern indie platformers.

The issue with this game is that a lot of these levels just are not good. You can tell by playing them that the developers were experimenting a lot with ideas, and developer interviews confirm this. This game's levels are a lot more interesting and unique than the first game, with a few new mechanics being introduced that add a lot of variety (poison mushrooms, wind, and more difficult piranha plants). Mario can also bounce higher off enemies allowing them to become part of the level design in all new interesting ways. Unfortunately, with experimentation comes failure and a lot of levels in this game are failures, with way too many deaths coming from obstacles that aren't telegraphed to the player.

All in all, I think everyone should try this game. Don't be put off by the difficulty or what people say, this game has a lot of creativity and passion poured into it, much more than a lot of later games in the series. It's just sad that a lot of the levels don't end up being that fun to play.