Ehndras, in Urban Dead, you're a human survivor during the zombie apocalypse. And/or, you're a zombie. As a survivor you're basically running about from building to building, making sure to be in a heavily barricaded one when you run out of AP's, lest you get picked off by zombies. You search for healing stuff, ammo, weapons, as well as other things like power generators, gas, books, spraypaint. Doing damage to other players is a common way to gain XP. The more XP, you get skills of various kinds. Different buildings offer different possibilities for type of items you can find. If (when) you die, you become a zombie, and then you can't search for or use items, but you get access to zombie skills and can claw at or bite survivors. There's a mechanism for returning to the living, as there are players with skills and equipment to resurrect a zombie, but they usually don't just go around doing that to anyone. There's a forum somewhere you have to beg someone to resurrect you, at one of the certain places on the considerably large map. Personally, my two characters are zombies and have been for a while. I used to be part of a large group who would organize raids on well-defended malls and such, but now I find there are still weak places I can take down myself. It's somewhat enjoyable to break in, bite everyone there once (infecting them) and maybe drag one or two out to the streets to feast on their corpse.
Shartak is similar, except in a native vs colonists on island(s) type setting, with natives, settlers, pirates, cannibals, etc. There's a lot of wildlife, so if you just enjoy shooting or stabbing things to get XP and increase skills, you can do that without having to worry about player politics. There's a lot more skill areas and item types, including some agriculture. There are some rare weapons floating around too apparently, but I've never found one nor have needed to. Unlike with Urban Dead there are achievements of various kinds, exploration of the map, the chopping back of jungle. Again, death is not permanent; here instead of Necro Tech reviving you your starting village has a shaman who, after you assume spirit form, can resurrect you.
Shintolin started out straight up hunters and gatherers, and over time has gotten some settled agricultural civilization aspects. Shintolin's death system is - well, you don't die, you become "dazed" if your hitpoints go to zero. Your actions are limited, AP regeneration is limited, and you need someone to get you some herbal tea to get back to normal. Oddly this 'death' is the most inconvenient of the three games. Skills are rather more important, and items can be crafted; buildings aren't just there already, but must be constructed. I.e., a stone spear is made from a wooden staff and a handaxe; and a handaxe is made from a stone and a flint. The wood comes from forests - either just searching, or cutting down trees (you need a stone axe for that); the stone from hills or cliffs, and again you can either just search, or you can try quarrying (you need various tools for that, as well as the skill). Everything is like this. You need to eat food; so there's agriculture, or gathering from the wild, or hunting down the animals. Unlike in Shartak, the animals don't just fight back, they'll run away, and many of them are impossible to take down by yourself (mammoths for example). The raw meat you get has to be cooked; fields need to be watered, etc.
I have to admit Shintolin is my favorite. New settlements are hard though. Back in the day my character (Tyrannicus) was part of a Nexus War based clan, but it's hard enough to survive without having to worry about other settlements burning down your stuff. Then again that's a major part of the fun, and now there are things like walls and towers. Still, my character's a complete nomad, and a total badass as well. I'd be interested in working with anyone who is interested in teaming up somewhere though.
