Yeah, it wasn't perfect Zim, but it was funny, used the fact that it was long dead for good comedic effect, and made me laugh which is really all I need from Zim.
The weirdest thing for me was wondering if that was really Kevin McDonald (it was). His voice has...changed, and it sounded like somone doing a Kevin McDonald impression to me.
But in general--more Zim is good Zim. More Gir is always appreciated.
Oh wait! More!! It was interesting because this felt like you could see some earlier ideas. Like the original idea was going to be playing with the idea of multiple dimensions, but then they just went "not enough money--give me a puppet show and some different animators!" Actually, I really loved Div's intro, setting us up and showing us that this kid is taking everything far too seriously.
The opening section -- with Dib lurking in his room for 'what felt like years,' confronting Zim in the yard, and having to get back into shape -- actually came straight from the comic series that's been running for several years now. (Which is pretty good -- not the best Zim ever, but keeping the right feel, usually feeling like pretty good episodes of the show.)