An interesting enough idea. The animation wasn't that great, but the blasts looked satisfying. The whole thing was a bit slow, though. Too much like an actual game, the main character had to aim and stuff to get the enemies. I feel like a bit too much time was spent at the start with him just destroying everything and he paused for a bit too long at the flag. He also only collected one power-ymup and hit one question block throughout the entire thing, which was a bit of a wasted opportunity. The plot was also non-existent, I wanted to know why the castle was torn down and why Mario became a boss. However, I did like how there was a lot of strategy involved in taking out enemies. That was lacking with the boss, though.
Keep it up, but try to do more with things that are right there, have at least some plot and spend less time on trivial things. Just remember you're not actually making a game, you're making a movie.