Well, I'm looking forward to it. It looks well done and seems to be a Mario/Kirby: Right Back at Ya crossover which will be a nice break from the Sonic crossovers. I just hope you don't pull too many elements from SMBZ (even though this looks like follow-up series). I think you should also make Kirby talk. Mario and Luigi got away with not talking in SMBZ because Sonic and Shadow could talk and made the connection with the audience. I don't think it will work as well if Tiff is the only one of the four heroes who talks.
This didn't lower my score, but that song is getting on my nerves. I don't know what it's from, but it has been used a bunch of times in other sprite intro/trailers.