Well for your first game it wasent too bad
But, it could use some work before finishing it such as:
#1. More responsive controls, when I hit Z or X it didn't do the action right away.
#2. Only two mushroom guys, add more!
#3. Sprites where very nice, sound was nice, animations where nice, just a little touch up here and there, also, try to add like a special move like an upper cut or something to that extent, then I would give this a 8-10 on the rating.
Keep up the good work though :)