Well, I believe this is the best sequel yet, but I’m not sure about the whole aliens angle. I definitely think that the language and the tone fit in with the prequel very nicely, esp the last line.

An Invasion of the Body Snatchers kind of feel to it. Or maybe that’s just the character’s way of rationalizing the quirkiness in the air. I like this sequel a lot.

Of course, he isn’t too sure he believes there is a severed hand holding a gun in his mailbox, either.
Hehe, I love that line!

Basically, all the people above said it right. Still, nice tone. You make something that could seem ridiculous seem halfway plausible, just due to the strangeness of the situation.