The first half of the movie is not that bad actually. Although there's not really too much depth in the characters, the story is somehow funny and generally OK with potential to get better, which it doesn't.
In the second half things start to turn for the worse, not only for the characters in the movie, but also for the viewer, who will be basically waiting for the story to come to its obvious end.
The previous user comment mentioned: "It's a love story, a road movie, a thriller, a comedy of errors, an 80's movie and most of all, it's a Jonathan Demme movie."
Well, please allow me to rephrase that: "It's a boy gets girl story, they happen to be driving around in cars, the thrill is gone as it is all too clear how things will evolve, there wasn't any scene in this film to which one might laugh out loud, it does have some slight 80's feeling and yes, Jonathan Demme really was the director."