I went with the kids to see it, and was pleasantly suprised. While it wasn't Airplane/Top Secret/Naked Gun funny, it was surely Scary Movie funny, and damn sure better than Epic Movie or The Comebacks...probably not saying much though. My kids really like Drake Bell (Drake and Josh), and he was funny, as was Leslie Neilson and Shooter McGavin (I'll remember his name later). It was a pretty straight takeoff on Spiderman with some random X-Men (Tracey Morgan as the Professor) thrown in for no real reason. A very sophmoric sense of humor is required, as there are plenty of crotch-shots and fart/booger jokes, and it's chock full o' silliness for good measure.
I think the pacing had more to do with getting things out of the way that most people already knew, and revealing that Tudyk's character was a Visitor was just to show how close and integrated they had become.