In few first missions enemy soldiers are very slow and not aggresive so there are many enemy cannons/tanks firing in unexpectable way. Further levels are (in my opinion) different than missions 1-5 (less cannons). I agree with a reliance on luck when wandering in the jungle. Booby traps, and mines are now more "invisible" than in original campaign (in original campaign I never lost any soldier on a booby trap).
I know that someone achieved mission 12 (and probably completed it) some time ago, but nothing more. I accomplished new campaign two times but it does not count.