Fantastic game if you played the originals, but probably not as much so for new-comers.
I love being able to go back and have challenges to beat each character using only left jabs, or getting a star punch every time. Those challenges make it worthwhile, but this is where the game starts to lose it's value. There are only three belts with 4 fighters in each, 5 in the last round. 13 fighters? come on I would have like to see 20, or at least 15. I more or less beat the first play through in a couple of days and thought that was it, then I realized they wanted me to play it again, against the same characters, only now they're harder. A little too reminiscent of Blast Corps on the N64. No one likes to beat something just to be told they didn't really. I haven't finished playing through the second time, because it got old.
Some people say the multi-player is fun, but it gets old quick. Very predictable, and there isn't much you can do with it. It's a little too controlling. If they let you pick the different characters instead of having to play Mac in different colored shorts, maybe I'd like it better, but it's definitely lame as it is.
If you can pick it up for cheap get it, if you stayed up late nights trying to finally get Mr. Dream or Mike Tyson, it's a must, but that is totally dependent on how nostalgic you are. I think that someone without that memory of sitting in his parents basement trying to get the timing just right back when that was the only way to add difficulty to a game may find this game wanting of something a little deeper, but it's just not really there.