Just finished this and to be honest it was a bit of a disappointment very strange ending and I felt the final area was a bit of an add on as it was pretty much the same as the other two.
Having to fight the bosses when the game decided, I use the term boss lightly was annoying. And the first one was a real pain with an aeroplane that flew like a bag of potatoes. I actually crashed into his plane which ended that fight rather neatly because if I needed to shoot him down I would still be at it.
Not sure if there is any replay value though I did very few of the driving challenges and there are a few minor side missions that I did not do.
Yet again I found that once I had four weapons I was happy with I did not bother with the rest, rarely used a companion though the bear was fun for a short while, and did not use any of the chemicals etc in my menu but I find that happens in so many games.
Overall even for me this game was too easy in fact I cannot think of a challenge bar the plane. Fun for a while though.