I enjoyed the game. So I assume I had fun with it?? A lot of gamers play a certain game because they are having fun with it. But maybe they are some who played without feeling enjoyment. That was boring weird tho.
To answer your title, I do have fun while playing a game especially if it is my favorite game. With a new game, there is no fun in playing it because I'm just learning to play it. But to answer your post, I haven't yet played call of duty.