The other comments cover a lot. I'll add that I, personally, wasn't into the whole buying-a-slave thing. I did struggle with losing humans quickly though, so I'm not sure if buying-a-slave is necessary to succeed in the game. If it is, it would be nice to have a workaround so that people who don't feel comfortable with that concept can still play. I think the improvements you made were very fitting. I'm not sure if you plan on doing anything more with the graphics but I quite like the simplicity. And the fact that you send the humans off screen and just hear what happens to them plays up the ominous, post-apocalyptic vibe, nicely done!