I never got into "The Gambler". Somehow I found it meandering and lacking in any real psychological drama. There didn't seem to be any deep inner conflict. Dostoyevsky's stories often feature protagonists that long for kindness but are neither able to find any or offer any. This makes the characters so compelling as they are ultimately cruel to the point of being masochistic.
However, Alexei Ivanovich doesn't come across as a particularly complex or tormented character. His character flaws are not disconcerting enough to be interesting. Yes, he is a gambler and yes he is sorry for this habit he cannot seem to give up but he isn't hopelessly fighting it or denying it. It is just not entertaining enough.
This might be one of the few Dostoyevsky novels that I didn't end up enjoying much.