Fun demo, it's a good twist to have guns in Mario. I just wish i could have driven the car!
Well first of all thank you so much for playing my game and making a video of it.
The car is not drivable but you can blow it up if you shoot it too many times.
And the next point is that I watched your video and I'm afraid you have not finished this game at all! If you pay attention to the main menu there is a button named "enter code"
You can find the code by finishing four "hidden" challenges and puzzles. I have to say that these hidden stuff are pretty hard to find and even harder to solve. I think you have missed the fun part!