Messages

- Apathy (one or more person requires less things to satisfy needs, but works slower / could also be done slowly if your fort is doing poorly socially and economically)
- Depression

First off you would need some sort of morale system.  Each colonist has a different maximum morale that they can obtain and a different threshold at which the following effects kick in.

In addition a tether system would be really useful.  Imaginary tether between two or more colonists.  They basically move around together and share tasks/experiences. 

Events:
Depression (reluctance to get involved in tasks, reducing moral of other colonists).  Triggered by a death or major event, or even lack of good food or entertainment. More prone so some people than others.  Spreads quite slowly but among st everyone.  You could even go a little further and make it the result of a full moon (of which there might be multiple) happening set period with only certain individuals susceptible.

Leading to;

Melancholy (inability/unwillingness to do any tasks).  Triggered once morale drops below colonists specific threshold.  Impossible to get out of on your own.  Tether another colonist to this person to essentially baby-sit them back to normality (both partake in tasks).  However, tethered individual will lose morale while tethered to the depressed person and risks falling into it themselves. 



 

[I personally would prefer if you went for a more gritty realism art style]

First up thank you for making this game.  It looks fantastic.  I have got a copy of PA and I just can't get into the whole theme.  There is after all only so much a prisoner is able to do!

However like the original OP said, I would be very careful about potential litigation (I am not a lawyer) of using the same art style.  Seems to me to be far too uncanny and therefore its likely it will be seen as a blatant attempt to hijack on the back of PA's success.  I don't think the theme is enough to justify the change, as it could just as likely be a free to play (developer sanctioned) mod.  Might want to check with a solicitor if you haven't done so already?

I personally would prefer if you went for a more gritty realism art style

I'm thinking that even something akin to Cannon Fodder, Sensible Soccer top down looks would be great.  You can definitely get in enough characterization using just hair colour, skin colour, build, hair length and clothing without needing facial features.