Impressive!
I'm impressed how well this came out!
I will however give out some advices and some things to improve on...
Constructive advices: As the movie started, I noticed that the outlines are relatively large. To help with this problem, try zooming in to help reduce the bold lines. As Shad starts skipping merrily through the road, the signs seems to be passing rather quickly and are a little unreadable. Maybe you can try to help that by having signs pop up on the sides in a comical manner. I also noticed that when Block-head is facing towards the viewer, he seems a bit stretched out and flattened on the sides. To fix this, try to work on your perspectives a little and study how to manage those tricky views. There's also the matter of frame-per-second issue as well. To create an effective animation, try to have the FPS at the minimum of at least 24. I recommend 36 FPS, but be warned though! The more FPS you have, the greater the space is required! However, it can make your animations more fluid-like and less choppy.
Praising: Because this is your first animation and you tried your best (which came out great btw), You came a long way for that! The comedic way the cartoon has shown now shows that you have potential for a greater cartoons to put more laughter later as your skills would improve. You also manage to put in a music video of the song in the flash that seems to fit into a TV screen that you made (Well done on that!). The fight scene was short, but it did give me more to expect great things later as your skills improve.
I have animated once, but it was rushed and incomplete. However, I learned quite alot in just a short amount of time and put forth my maximum effort myself. I hope you improve yourself and become a great animator in the future! As far as I seen this animation, It's pretty well made! Congratulations!