I don't feel that zombies would be a good fit for Rimworld although the ability to add them as a mod would be nice.
I do feel that some other kind of non zombie virulent plague might be an interesting idea. For example you capture a raider and they infect your warden with space flu and then spread it to the rest of your colony.
Infected colonists are unable to work and without medical equipment or supplies have a chance of dieing from the illness. Maybe even have a way to minimize spread such as quarantine and hygiene practices.
I do feel that some other kind of non zombie virulent plague might be an interesting idea. For example you capture a raider and they infect your warden with space flu and then spread it to the rest of your colony.
Infected colonists are unable to work and without medical equipment or supplies have a chance of dieing from the illness. Maybe even have a way to minimize spread such as quarantine and hygiene practices.