Defeating Vamp as Snake in Act4
One of the best ways I've found to defeating vamp is to hold down x, laying all the way down, hit the triangle to roll over, then, use a machine gun (the patriot has infinite ammo--recommend)...press L1 to aim then R1 to fire continuously...VAMP will avoid most CQC and you can deplete his life...once you've pretty much depleted his life to a very little...hold x to stand up, turn your back to vamp, vamp will charge you, turn back around and hold L1 and R1 to kill him.... one thing I forgot to mention, while you are trying to kill vamp, make sure to have the SYRINGE equipped... as soon as vamp is down, run behind him, hit R2 to switch to CQC, then R1 to kick him and put in a choke hold, the game should tell you to hit triangle to inject him WHAM! VAMP is done for this scene...