OK, not great.
The main plot of this seems to be a Goomba getting a new girlfriend, so what's with the 'We'll be kings if it works!'
Secondly, 8-bit Super Mario Bros sprites and more-than-8-bit Super Mario World backgrounds are not a good combo.
But don't get me wrong. There were some good bits. I quite liked the use of the Pink Panther theme, although the remix doesn't have the same stealthy feel. Perhaps use the original instead.
Finally, you missed out the fight scene between Mario and one of the Goombas. For that reason alone, I give this a 2/5 and 3/10 instead of a 3/5 and a 5/10.