It's funny though that the sandbox nature of the game is so strong that you can notice how intricate a mission is 'first-time' on some levels whereas on others you luck into a really effective way of beating it and you're like 'that was it?!'
I just assume now that every mission has more layers than an onion. I'm really looking forward to beating the game and playing the levels not to beat them, but to explore them and get the secondary objectives.
I cleared one mission by essentially running straight into an enemy base, throwing smoke everywhere, then jumping in a jeep and driving off with the prisoner in the back in the confusion. Mission complete. I think you're supposed to tail him or something.