I liked it.
The battle scene was the core of your flash. After watching it, I don't remember anything else. It was somewhat repetitive at some points, but it was awesome and looked like some ideas AlvinEarthworm himself could pick up.
I thought your sprites were kind of too small. During the talking scenes, you could've made them bigger. I know making them small earns you some space, but when people talk, nothing happens... Oh well. It's your choice. Keep it up!
Not a fan of sprite movies
I've never liked sprite movies, but I see enough work behind this flash, to expect you to actually take my advice anyway.. So here goes:
"Zooming up" on sprites almost never succeeds, so if you don't know much about camera angles and such, don't try it - at least not that close.
The sound effects didn't all match the same style, but were generally good in both choice and quality (some generic Mario sounds together with something that reminded me of Worms.)
Try not to use the same sound effect twice though.
A smaller resolution size might have been better for a sprite movie.. I don't watch enough to know though.
I enjoyed the part where Mario & Luigi played tennis with Bowser as ball, the music was a little too high at that point though. Turning it into background music, instead of a replacement for all sounds (Like in Scooby doo) would have been better.
3/5 & 5/10 from me
Awesome
This is some great sprite-work, with a couple of funny lines that make it a completely enjoyable watching experience, can't wait for the next addition