I did explore different ways to approach the levels, FFS. It's honestly not as cool and nonlinear as you claim. But I'm used to it having argued with Fullbleed; fanboys always exaggerate. D:
It wasn't enough to convince me the gameplay was super awesome and nonlinear. Ultimately, whenever I got in a tight spot with TEN ASSHOLES chasing me down, the sneaky silenced weapon approach was all that worked. I played the game on "hard" and even when not on Delta mode there's only so many bullets you can take before getting raped. And that number was certainly far less than the amount that would have been shot into my face had I not been sneaky most of the time. Being in the open in such situations usually means you're dead. Hell, simply using a gun without a silencer could mean death, especially when there's a boat following your every move and shooting at you from 900 yards away.
I jumped up onto things at random to shoot from there. I sped up to some guy at 60 MPH only to grab him and hold him hostage. I ran over lots of guys in humvees and even kamikazed the one I was driving to take out another most of the time. I shot exploding barrels to get everyone's attention before assaulting them from a different direction. I used speed mode to plant C4 on a patrolling tank and then run away, all in the span of three seconds, so I could get through without going around the base. I even got through a forest and across a river with zero ammo using the sleeper-dart thing.
Time and time again, the most effective way to approach any situation was to be sneaky. Since everything you do takes away your suit's energy, and since your suit's energy is the only thing that keeps you from dying from every third bullet shot at you, you're definitely limited in how much Superman bullsh*t you can pull off at any given time. Sure, when there's one or two guys around you can do whatever the f**k you want, but there were times (and it seemed too often) that the entire Korean army was hunting me down.
But, all that said, I got through the game without any real problems. "Hard" difficulty was barely hard at all. There were annoying points -- the choppers, the boats, the fact that the vehakals usually blew up before I could do anything useful in them -- but overall it was much, much easier than Far Cry. And I played Far Cry on the third of five difficulty levels rather than the third of four. D: