Was recently reading John Wyndhams post apocolyptic epic Day of the Triffids in it it mentions that lonlieness becomes a factor for the main character as he loses contact with people. It got me thinking how about adding some human interactions to stave it off the mental, food sharing and similiar type things. add some spooky effects maybe hearing things seeing things that aren't there as you become more and more deranged. It could encourage human interaction a little more or simply make it a little more spooky to play alone.