i guess i will state my opinion. what i like about killer7, is not being able to make sense of whats going on, and observing the fucked up things that constantly happen. i don't much care about the plot, other than the simple fact that i don't understand it, its messed up, and its awesome. that makes the game palatable, for me anyway.
but the link is a nice read for those interested in making sense of the game, as it isn't really spoon fed to you.