It's just not there
Now, I have nothing against the use of Homestar and Strong Bad in here. I happen to love the Homestar series, and personally think that they're hilarious. And this movie does have several good things going for it: It's got good graphics, and the pun on Homestar's name is fairly good (Homestraw Clocker). There's something, though, that's stopping me from giving this a good score.
It's not funny. Or, you know, interesting.
I won't hide the fact that I've never really been a fan of these fruit/clock/portal toons. They never really interested me. There's a lot of stuff funnier than this out there, and it doesn't take too long to find it. You could, you know, even check out www.homestarrunner.com to find stuff even funnier. It's sad when a parody is significantly less amusing than the original work.
Timing on jokes are off. E-mails have no comical content and don't even really reflect SB's personality. As long as we're talking about personality, HC doesn't show any of HR's personality, either. Any satire, slapstick, or verbal wit is dry, boring, and simply doesn't work.
The score of a 3/10 is a gift. After typing this response, I was seriously thinking of lowering it.