This is an okay drawing, nothing too special. The purple outlines don't really work, and adding a background for him would have been nice. the mustache is colored wrong as well.; it's black rather than brown. The detail is decent at least, and if it was done just as a quick job then it turned out okay. Pales in comparison to your later work though, you've certainly improved since this.

I've always thought that Waluigi was the mario version of robby Rotten from Lazytown.