Yeah, getting 30 mellons in every stage is tough, but more in the insufferable way.
Each melon has to be found, which usually means sniffing about every pixel of the huge, empty levels. Then, there are things like the melon stacks, which become nigh impossible on the later stages.
It's simply TEDIOUS in trying to locate that very last melon in each stage and quite IRRITATING when a single, tiny mistake (i.e. one single death, missing a melon stack/race, not knowing that a paramelon won't respawn after it hits the ground, or that paramelons even exist, getting hit while eating a melon so it falls off the screen) will mean that one has to reset the game and try the entire level over. There are too many aspects of that game that make it an annoying play.
Oh, Nintendo, you could've done so much better...
But enough ranting. Yes: getting 30 melons in every stage is a difficult task.
Aid