Great Series!
So far I am loving this series. The humor is fantastic, and dispite the DBZ theme it fits in well with the Mario world as we know it. The action is absolutely flawless and the visual effects and sounds are wonderful. Not to mention you captured the personalities of the characters pefectly.
I feel I have to speak on Sonic's backstory a bit. It was very well done, dramatic even. You also set up Mecha Sonic as a real threat and set up the rest very well. However, and this is a personal peeve of mine, I do not like it how you apparently killed off the other Sonic characters, including Eggman. That is just too sad, but the drama works. (of coarse, given the DBZ theme, I wouldn't be surprised if they all were miraculously saved or brought back somehow) Otherwise, a great way to set up the rest of the story.
I also hope we get to see more great fights, and possibly more character battles. Keep up what your doing now, I look forward to seeing what else you do.