There's something to be said for games that revolve around a single joke. If you've wrung every possible guffaw out of a game within the first half-hour, you can just close it and move on with your life. In theory, Goat Simulator benefits from this structure. You're a goat! Everything is broken! From there, it's up to the player to decide whether there are further punchlines to be delivered.
Of course, this does not apply if you're under some kind of obligation to see a majority of the game's content like I was. I spent a good 4-5 hours wringing the game dry, and I was reaching for entertainment around the 20 minute mark. Regardless of whether you find Goat Simulator's core gag amusing, it's hard to ignore the price to content ratio.