One Night at McCool's is one of those comedies where you have to suspend disbelief in order to enjoy the premise otherwise it won't be funny at all. It's a black comedy and in this case it means that you will either love or dislike it. I am kinda in the middle of that. Since I have some mixed feelings.
The premise is that Liv Tyler plays a woman who manages to manipulate every man in sight that she wants something from. And I would have been able to accept it if only that Liv fails being convincing as the femme fatale. The problem is not that she is not sexy or anything. She obviously is. But that is all there is to her. She has no depth or personality. Most of the time she was downright villainous and it was hard to have any sympathy for her. What makes these femme fatales so fatal is that despite their badness they still have the audience's sympathy because there is more to them than meets the eye. A good example of a femme fatale is Kathleen Turner in Body Heat or Sharon Stone in Basic Instinct. But Liv Tyler does not come even close to the characters in those movies. She wished. Now this is something you can overlook if you find her super attractive. However that is very subjective of course. What is left it is the way the story is told. We follow a few characters each with their own viewpoint and perspective on their dealings with Liv's character. I must admit these different perspectives made it quite funny. For a while at least. However most of how the story plays out is just absurd and not really funny. And I think it has to do with the people not acting like real people but more like cartoon characters. Every bit of mature theme that is paid attention to then is made a joke of and hard to take it seriously. Strangely enough if this was handled better it would have been more witty. The cast do a decent job and I think it is because of their efforts that makes it worth you while.
Still it's hard to recommend this one since a lot of in this movie is hit and miss. Even if you managed to get into this the film never manages to give you a decent conclusion. Which makes it feel like you have wasted your time a little. Then again it does depend who you are rooting for.