Pretty good
I remember watching this waaay back, and it's still pretty awesome. I like the fact that you added endings for both characters, letting the viewer choose their favorite. Oh, and one of the reasons I'm also writing this review is to give you a heads up that some jerk took this flash for their self and posted it on youtube without any credit towards you for it (he's using it to boost up visitors on his website). He cut out mainly everything in the beginning where it says that this was all produced by VGDC. Perhaps you want to give this guy an email to tell him to give you credit, or delete the video all together (I also told him to do it). (For any Newgrounds staff, this next part is not promotion of any type, it's just naming the video where he can go and contact the youtuber to try and fix things) It's called "Sonic vs Mario Video Who Wins ? Mario vs Sonic You decide at the end of the video" by UpdatedEveryday. Well, I hope you can clear things up, I hate to see plagiarism -.-;;. Especially when it's really good work like this.