Ripped off humor = Unoriginality
I'm surprised that nobody else here has picked up on this. In fact, I'm not even sure if YOU are aware of it, but it's been done before. In fact, there's a movie called Shawn of the Dead. Which includes two idiots trying to save the world from an invasion of British Zombies. Including a scene where there's attrocities going on outside of which the lesser idiot is completely unaware. Also including a scene where the two of them are randomly throwing things at the zombies. One thing in particular about that scene, is that in your movie, the scene involves a PS3 and a Wii, in the Original movie, the scene involves them arguing over a record collection. If anyone who watches this movie is even remotely entertained, then you should check out Shawn of the Dead... it's hilarious. The "Borat" scene wasn't in Shawn of the Dead, but still, it's humor stripped from the Borat character of Sacha Baron Cohen, who also happens to be British.
Ultimately, it wasn't a bad movie, but give credit by labeling it a remake or parody. I really enjoy some good British humor and I know that there's not such a huge following in America, however it's not so out of the way as to rip it off and try to pass it as your own without SOMEBODY noticing.