>>531702140
It's like you have an RTS game running on a huge map, with squads belonging to different factions patrolling around and sometimes fighting each other, but instead of a big faction you control an independent group of 1 to 30 people. With mods you can get up to 256 people, though most computers can't actually handle that many. You can wander around fighting people, or build towns and defend them against raiders. There's no story and no quests, apart from what you choose to do.
It could be argued that it's an RPG, based on its mechanics, but it's really nothing like any other RPG I've played.