Heh, your best yet!
Really liked it, much more action and all that stuff. It kinda felt like a conclusion, where the heroes got back the emeralds. You better keep up the standard and shoot above it ;)
Ok now for, well you know. At one time, when luigi was retracted into the shell, I saw a bit of his arm sticking out, is that supposed to be there or what?
Next, the zooming in when waluigi hits the screen (it is the screen right?) makes waluigi look more like a bunch of pixels, and that doesnt look good, although Ill let it go because its a sprite movie.
Music fit in well with scenes, and the selection was good. Plot kinda concludes and deepens at the same time ;)
One last thing: When mario is on the block that previously had the fire flower, and the view becomes 3D, the block faces dont match, and extra black pixels on corners isn't good. That's like the only piece of graphic I could think of that needs to be improved
So anyways, keep up the good work, and hope episode 7 is even better (not saying this wasnt)
Score: 9.1/10
P.S. Nice joob on getting your own section for the Super Mario Bros Z series!