A few suggestions.
First of all, I gave it a 2 instead of a zero (and I'm going to be nice and NOT blam the shit out of it) because it's your first attempt at flash. That doesn't mean it wasn't pretty boring. I like to see Sonic vs. Mario as much as any true gaming fanatic, but there could have been a lot more things you could have done to make it interesting.
For instance, it would have been a little funnier if Mario had killed Sonic, like Sonic killed Mario (don't be biased). Secondly, it would have been funnier if when Sonic got pummelled, he lost all of those stupid rings he collects all the damn time.
I'll go check out the other Sonic vs. Mario. If it's the same thing, I'm not going to review it. Peace. So says Dr. "stupid gold rings" Manhattan...