I finished the book last night, and have been mulling it over all day. I think the joy of an unreliable narrator written by a skilled author is that you don't really know for sure - and you can change your mind, change it back again and still never really be sure. There is no definitive version of events.

For me, I think that virtually all (if not all) of the murders were in his fantasies. He is unraveling throughout the story, becoming more and more unhinged and psychotic. So many of the things he thinks he says out loud are probably not said out loud. He's off his face. What is going on in his mind and outside in the world blur. A lot of the murders are unfeasible. Sure, you could get away with killing a homeless person - but the ludicrous and farcical multiple deaths involving power tools and the amount of blood and carcasses? Unrealistic to the point of the author having a laugh.

And it really does seem to me that alongside being a scathing criticism of 1980s consumerist capitalism it is also the author completely taking the piss out of pretentious yuppie culture. He's exaggerating, pushing further and further to see how much he can get away with, how much his readers will believe - or at least be entertained by.