I really hate the idea of writing a review that doesn't offer anything insightful a year after the Flash's being submitted, but I just wanted to say that this was some really, really good work. That much could be said of any SMBZ episode really, but you introduced my favourite characters into this one, so this is the one I'll choose to express my approval.
The fight scenes are impeccable and work seamlessly. Each character seems really true to their roots, too; you've done an excellent job of capturing the feel and dialogue they use.
I look forward to going onto the next episode (and possibly reviewing a newer one than this), and hope that my favourite characters continue to strut their stuff! Congrats!!