To kill the driver of the dump truck in the junk yard before it automatically kills Jenny on it's second pass you have to shoot the glass on the drivers side with gunfire and when the glass breaks the truck will stop.

In the Havana level Freedom Fighters just before continuing to to El Capacito tell your men to take cover behind the large pointy statue and then shoot down the helicopter with RPGs. You'll need a few RPGs to bring the helicopter down, if you need more because you've run out go back to where you shot the APC vehicle and there will be supplies there.

To reach the final chapter in the game you have to move Kane in the correct direction when you have stopped the cargo plane by grabbing Jenny. Move Kane towards the village instead of the helicopter to progress.