LoL: Oh Yes And Spiders Clever, but lacking
It comes down to the pacing, dialogue and voice acting. The jokes should be a little punchier to be effective, and that goes for the dialogue as well, remember LESS IS MORE.
Mostly, though, I think the voice acting is cast wrong. The characters sound older than they should be and bland. There needs to be energy in the characters, even to the point of cheesiness. For something like this, camp is WAY better than bland. Nail this and it'll be 10 times better.