Challenging and enjoyable, but kind of falls short compared to the original.
Graphics-wise, the game looks great. I don't mind the fact everything is bigger. It makes since the levels take up two screens. I love the new expressions Yoshi has. Regarding gameplay, the controls seem not as tight as they were in the original. The levels are bigger, which is always a good thing. I kinda enjoy the fact that items are not included in the game. It makes getting a 100% in a level that much harder. More challenge is good, imo, because NSMB severely lacked it. I don't care that it's so easy to get extra lives because you need them. The only thing that has really bugged me so far is the gap between the screens. It makes so much more sense to me if they didn't treat that gap as an actual gap in visual space. If the view was just continued on the top screen, it would have made for an easier time. The way it is, it's just tricky finding some things and I personally have had a really hard time shooting moving objects on the top screen. The target minigame is near impossible. Maybe I just need more time to get used to it. Right now, it's really bothering me.
I have mixed feelings about the sound in the game. The music is decent. But, I think coming into the game, I was expecting something like the music of the original. It's calm and simple in YIDS. As far as the sound effects are concerned, they're alright. They changed some of the sound effects (why, I have no idea). There's no longer a "sparkle" sound when you unleash stars from a ? cloud. And when you collect the stars, it sounds like you're gathering coins. What the heck? Maybe I'm just a purist. In general, I'm actually disappointed with this game's sound, and that's why it earned the lowest mark on the rating of all the categories.
Overall, I do highly recommend this game, to lovers of the original YI and newcomers alike. If you wished NSMB had been more challenging, you will come to love this game because it IS challenging. Some elements may take some getting used to, but the game as a whole is really solid. Yoshi's back. :)