Rot World is 65 pages of information dense zombie RPG.
The book contains almost no background, flavor text, setting or "fluff". It is almost solid rules, mechanics and examples of play.
The heart of the game is the Action Table, a single table that can be used to resolve any action or conflict. Much of the rules text is examples of how to implement and interpret this table in play. Everything from determining the contents of the Kwik-e-Mart on the corner to combat against a horde of zombies.
I am not a fan of crunchy games, but in this case I will make an exception. This is not crunch for the sake of adding extraneous detail or rules for the sake of rules. Every rule and piece of crunch is here for a reason and will likely be used in play.
The sections on creating zombies and the breakdown of civilization are gems. A very wide variety of options and styles are presented with individual gamers being free to mix and match to suit their own tastes. Fast zombies created by a toxic waste spill out to eat your liver in a slow spreading infestation? Radioactive, intelligent, but slow shamblers consuming all flesh in a fast moving apocalypse? Psychic zombies from outer space? Take your pick.
Rules describe the rate of spread of the infestation, and the effects on various aspects of society. Very useful for those who wish to set their games at the beginning, middle or end of the outbreak.
This is the best product to come out of the OSR I have seen yet.