It's Fallout 3; a good sized world with interesting encounters and "what's over the next hill" exploration. Once free of the introduction there isn't any hand holding unless you opt into it via a Quest, so you're free to do as you please, making friends or purging the entire wasteland of life. For £5.29 on sale or free with Prime you can't really go wrong with this, and even if you don't like it there are total conversion mods out there to make it into a different game.
