Characters don't HAVE to be 'likeable' for you to care...
No this movie didn't have an overly 'likeable' character, but that is no reason to dislike the movie.
I've seen plenty of movies that had likeable characters, however, I stopped caring because the movie itself would just drag.
Just as an example, I tried to watch the movie '3 Days to Kill' and Kevin Costner is pretty much the classic hero -- trying to make things right with his daughter, killing the baddies with ease, making jokes etc.
But I just didn't really feel for him or like the movie much.
During 'The Gambler', yeah I realised early on that this isn't a traditional hero and not really a good guy in the traditional sense -- but I still wanted to know what would happen, and what would become of him by the end.
It doesn't mean you have to agree or even 'like' the character, you can still be interested in them and their pursuit.
Not every movie needs a'Will Smith' or a 'Brad Cooper' for us to be invested in them.
It can still be fascinating.
(human nature, that is).
It can definitely work and is a nice change.
To me anyway!