I found so many things wrong with this movie, it's hard to know where to start. For one thing, it's not funny. I think I laughed out loud about three times. Even worse, there are many times when you are expecting--make that hoping--that something funny is going to happen, or someone will say something funny--but it doesn't happen. For example, there's the go-carts, a scene that wants to be played for big laughs. What is funny about two men driving go-carts? Nothing. Something MIGHT happen along the way that's funny, but doesn't. They race, they make crazy turns, and they yell loudly. And it seems that when they discovered this wasn't funny, they had to add some slapstick to end the scene. Trouble is, it's so unbelievable that it's painful... and unfunny.
Related to that are scenes and dialog that go on and on without making any contribution to the story or to the exposition of the plot. Like when the sister takes a drink out of the refrigerator, shakes it up and drinks it while her mother makes a face. And then someone starts talking. What is the point of that action? Why did the camera linger on it? Why do we care?
The worst example of this is about 2/3 of the way through, when the two lovers run off into the night and end up telling each other how much they love each other. This is perhaps the longest scene in the movie, but it serves no purpose. What is it doing there? To show us how much they love each other? We already knew that. Character development? Hey, the movie is 90 minutes old--it's a little late for that.
And the editing is so awful at times, it makes one cringe--such as when Kutcher is climbing back into the basement. One moment he's fiddling with the window, and a second later he's standing on the floor next to the bed. And at the end of the go-cart scene, the two guys are surrounded by cars and trucks and the sound of a crash; and in the next moment, all the traffic is flowing smoothly around them.
But I think the most disappointing thing is how little the movie makes of its premise. About 75% of the conflict in the movie has nothing to do racial issues; instead, it has to do with a guy trying to get along with his girlfriend's dad. In this way, it is very close to Meet the Parents. But Meet the Parents was funny because it had a lot of funny jokes and situations, and it honored its premise. Guess Who has very few funny jokes, but worst of all, it doesn't do much with its premise. And the "black joke" that is supposed to be a shocking, critical point in the drama isn't even all that offensive.
About half the audience at my screening walked out before the movie was over. Too bad. I wanted this to be a good movie, but I guess the writers and director didn't want it as much as I did.