How does Edgar Allan Poe's "The Black Cat" reveal an unreliable narrator?

In "The Black Cat," Poe's first-person narrator reveals his unreliability throughout the tale. 

First, he calls what he has done--cut out the eye of one cat, hang that cat, try to kill a second cat, and axe-murder his wife--"a series of mere household events." Anyone who would think these were "mere household events" is probably not living in the same reality as the rest of us, and cannot be assumed to be a reliable narrator. He also says these "are nothing more than an ordinary succession of very natural causes and effects." "Ordinary" and "natural" are the last words most people would use to describe what happens in this story. That the narrator would use these terms should cause us to question his state of mind. 

He would have us believe he was a kind, compassionate person who has had some momentary lapses. He later blames his alcoholism ("he blushes to confess" that he drinks) for his cruelties, but provides no good excuse for cutting out the eye of a cat--that is a horrible, unspeakable thing to do no matter how much the narrator tries to normalize it by blaming it on drinking.

Moving on, he says he hangs the cat out of an impulse all of us have had to do a "vile or a silly action" just because it is forbidden. Again, he is trying to rationalize or normalize a sadistic act. Yes, many of us do "silly" things for no good reason, but that doesn't include torturing and killing an animal.  

Finally he blames the second cat for his wife's murder, calling it "the hideous beast whose craft had seduced me into murder," and ending with characterizing the cat--and not himself--as the "monster."

His very odd view that his behaviors are mere "household" acts, along with his inability to take responsibility for murdering his wife, call everything he says into question. Was he really so good to his animals as a child? Did he really only "accidentally" hit his wife with the axe? Is it really the cat's fault his wife is dead?