Funny and awesome!

hm.... its dont funny...
is boring !

The animation isn;t bad at all. The 'story' or entertainment is kinda lacking. Having to wait for mario to get back to the screen and walk is a bore. Cut the walking and waiting by zooming to the next segment you want us to see instead. Like in movies, do you want to watch a character walk to their car and wait for them to leave or just cut to them in the car on the street? So zoom in the action and jump to the interesting parts. Your stage is maybe too big and not on the green hill zone bg only, that's why there are big blank white rectangles on the sides of the flash. You might also want to add a loading bar page and replay page in the beginning and end of your flash (just look up some simple tuts here on NG no biggie).

I know your proabably new to creating flashes, but this is just terrible. Slow framerate, little to no story, and those ugly white barriers.

P.S - No one does Mario vs. Sonic flashes anymore. They've been done to death.

not bad. liked from what i've seen so far. wished it was a little closer, more details on the sprite animations.