On a whole, Far Cry was not difficult, even on the highest couple difficulty settings. There were just some stand alone points that were difficult because of bad design.
The next to the last boss fight where they stick you behind a podium with no cover was just stupid.
It really highlighted the fact that there AI really wasn't all that great. "Gee, you can make AI that has 5 extraordinarily tough guys shoot grenades. Awesome job."
The outdoor levels were too easy in general because the AI usually couldn't find you. Indoor levels were generally okay until they realized that one v one, or four v one their AI just couldn't stand up to anyone who could click a mouse button so they had to throw in 10 or 20 guys at a time.
I guess my real gripe is that indoors their AI doesn't have as much flexibility and it showed through fairly often, especially when they tried to make up for it in quantity.
Outdoors they worked better in squads though often you never saw that because you were looking at them through the hairs
I liked the weapon approach just fine, it's when they stuck a save point three rooms *after* you stocked up that it was annoying. Really there were just 4 or 5 points where they needed an extra save spot so you wouldn't be backtracked past two or more tough battles.