All of the characters are animated so off-model, you'd wonder if they were ever on model in the first place. Almost like they're made of jelly. But then again, it's a signature of Brazilian animator and W-P-S art thief Golfinho, who also helped out here as well. There's also instances where there's a background and instances where there isn't. In the same general location.
Also please be careful with using video game music. Game companies like Nintendo own those tracks and have the right to take it down. Newgrounds themselves would also take it down to avoid issues with Game companies.