1781 - Law Abiding Citizen

It's rare that you can spend 80% of a film more-or-less being entertained by it, only to have it's ending come and you become completely resentful of the damn thing.  I found the premise titillating and I was hooked enough to want to know how it would end.  I won't go into spoilers in case people still want to see it - but this is essentially about a man whose wife and daughter are murdered and the person responsible gets off on a light sentence by making a bargain, and about how the widowed husband decides to make the law learn a lesson.
Considering it's a message film I found the message to be buried a bit, and completely abandoned by the films final act.  I bought into the face that Gerard could make all of this work, but I don't buy into the ending - at all.  Feels like an awfully large cheat.   Again, no spoilers and judge for yourself.

If you're a fan of the premise (as I was) check it out, and hopefully you aren't as disappointed by it's ending as I was.