IMPMON!!!
The final animation in the credits was totally random and seriously awesome, and since so many others have commented on things of that nature, I'd like to go on about music because it upsets me that a great flash video like this gets lesser ratings for no sound or music.
As one other guy said the Audio Portal is indeed a great place for free kick ass music, but OCRemix.org has some great game remixes if you're ever looking for some and this website also has original music from several video games if you're intrested:
http://elitesmashhackers.org/2010/07/
30/lavos-is-about-11-years-late/
Now go and create, you gods of the internet!