Soldier of Fortune: Pay Back Q&A

iv killed all the enemy, now i dont know where to go from here, how do i move on from the waterfall, i cant find anywhere to go. Id REALLY APPRECIATE sum help.

I reached the mission where you are in this little area and your getting shot at by a helicopter and I can't find a way to get passed this mission does anyone one know how?

I reach the mission with the caves and battle my way to the top, kill everyone. Where do I go from there? All mine openings are either closed or a dead end.

I'm at the the level were a Helicopter flies around and Guys keep respawning. Ive killed all the guys like 50 times. and can't take down the chopper. How do i beat this part