Funny if you've seen HR already.
Well, I liked the Homestar Runner song once I got the refrence. The little movements they made like Gaz jumping added to the flash in a good way. and all the characters look accurate for something made in flash.
But the frantically moving "Bonus stage" lips didn't work so well for this, I mean It's a song! Lip sync should be top priority. And Zims eyes looked more like a gradient rather than two red eyes with kinda square light reflecting off them.
All in all, I didn't feel like I wasted my life watching this, and thats what matters.