While it definitely isn't as good as Super Meat Boy, the original Meat Boy still stands as a great game even today. The levels are really hard. I have many fond memories of rage quitting at elementary school because of this game. Some of the most anger inducing levels in flash game history can be found within this game. The difficulty, however, is part of the reason why I love this game so much. (Fuck collecting all of the bandages, though).
There's more to it than just the hard levels, there are plenty of characters to unlock and this game introduced me to Super Meat Boy, which was one of my most favorite obsessions. I'm so glad I got into this.