do you have far cry 3? cause i just beat that and probably one of the better games i have ever played. Great story, you shoot shit the whole time, open world, etc.
BL2 is also amazing, put a full playthough on it, all missions and everything and it was pretty fun in coop.
Hitman is very story driven, but is more like here is an arena, deal with the situation, then you move on too the next arena. It isnt as plain as the arena to arena made it sound, i think it is great and beat it twice.
all are easy game to be serious or have fun with.