VERY heavy handed as far as the forced guilt trip, explaining that you're MURDERING...INNOCENT THINGS...FOR MONEY!!! (people also tend to associate innocence with cuteness, not so much with vermin) Far too much explanation of the obvious UI, you have to trust that people aren't complete morons. The increase in required clicks for any amount of forward progress is also incredibly steep, at 5 kills it became far too tedious to continue any further and I barely made it to that.
If you have to TELL someone how they're supposed to feel, then there's something wrong, one excellent example of what you're trying to accomplish is a game called "Exoptable Money" (http://gamejolt.com/games/exoptable-money/36236). One thing that makes that game so successful is it begins by making the player feel like getting as much money as possible is a benign goal, slowly feeding the player's greed until they are finally presented the option to substantially increase their profit margin by doing something horrible.