There's a lot I could mention in this review, but I'll cut to the chase: This is the most impressive fan created game I have ever played. Sure there are glitches and little things I could nitpick, but when you consider how much depth there is to this game, it doesn't matter.
I've played earlier versions of this but now the game really feels complete- it's enormous and my only complaint would be that I'm never going to have the time to sit down and play it all the way through. I didn't really like the story, but I don't tend to like any fan stories when it comes to established franchises like Mario.
Anyway, this is fully deserving of a 10 out of 10.