Maniacal
the green Napoleon
did you get them right first time, or did you have to adapt your tactics through trial and error? did you change your weapons and use the variety that was available to you? Im not going to argue that battling ten enemies that randomly spawn in a fixed map isnt linear, but it certainly requires some thought and an expansion on the standard cover and shoot strategy.
I don't see how there was any expansion upon shoot the enemy and don't die. The one mission I did take a different route (than my roommate as I saw him play through it first) was the one where you take out the Russian base in the snowstorm. There was no real change in tactics or much thinking for most of the missions, I may have adjusted my cover or been lucky and found a useful gun (like the dual-akimbo in the Brazil mission where you are "chasing" (not that I think he can even actually get away afaik) which I found to really help when I needed to reload my main weapon and an enemy popped up and for running and gunning) but that is hardly more than a small thought if I even gave it more than a second's thought.