If you play enough of the game, you'll notice that it becomes extremely repetitive..
Even though I did enjoy the game for a while. Eventually, at some point, you will notice the repetitive nature of the game.
Go from point A to point B. Run, grab, kill, run, shove aside civilians, disguise yourself to escape military harassment, run, run, grab, kill, repeat ad naseum.
Even though the game 'attempts' at some variety, you're basically dealing with civilians, the same basic soldier, tanks, helicopters, zombies, and the big mutants.
The same units for every part of the game.
Don't get me wrong, the game has it's moments of fun. However, I wouldn't give it a score over 8.5 at most. Still worth some of your time.