This could use a lot of work.
I think that this cartoon would be better off if you used your own graphics. Even if the graphics are bad, at least you'd have some artwork and design that you could call your own. The characters you chose look awkward when put in front of the background you chose.
I must hand it to you though, the background is very good and the Dr. Wily music from Megaman in this definitely makes this a lot better. Unfortunately the overlapping music let down the great music choice.
Tip: Only put in one audio track of the Dr. Wily song to avoid having it overlap.
I can kind of see where you were going with Shrek and the Wii but the overlapping music was excessive and just plain irritating. You shouldn't have this problem with the overlapping music.
Overall this would be a lot better if the sound didn't overlap and if it had original graphics. Good luck on your future projects.