I have been following the development of, actually not a game but a free mod, that placed the original game on the top selling list on Steam for weeks.
Im talking about DayZ dayzmod.com a free mod for Arma 2.
The developer of the mod said they registered 10-12k new players connecting daily. (Some of who might have bought the game a long time ago) .
Whats interesting is that I dont think any publisher would go anywhere near the mod.
The most interesting features in my opinion is:
Your character and equipment is persistent on all servers.
If you die you loose it all and will have to start over
Day and night cycle on server that changes with real-time.
You need food and water to survive
player vs player
Start without any weapon, you must scavenge towns/farms on a huge map (225km2)
No global chat. You can chat if you are within 40 or 60 meters. Same with voice chat.
No easy way to refill life. You need to bandage up if your bleeding, and, you might pass out when hurt. Only way to refill health fast is by blood transfusion, and that cant be done by one person alone. Alternative is to hunt, and make camp fire. For that you need to find matches and firewood.
You start without a map or compass. And even when you find a map there is no indicator of where you are. You need to find a land mark or figure out close by towns.
its pretty much the opposite of your regular FPS in terms of concern for helping the player to survive and telling the player how to play.
As said the mod is making Arma 2 best seller for weeks on Steam. But doubt any publisher would have touched the concept. The developer has now moved for to Prague and is cooperating with the Arma 2 developers. Not sure about details of their arrangements.
If you haven’t already I suggest you check out the dayz site, interesting to see the game develop, the try and errors, the massive amount of “so called hackers”.
And +1 for Arma for letting players make mods in the first place. Rare feature these days.
Here is a video from the game:
http://youtu.be/rLh4A9MS5k8 (an older version of the game)