Hint Code: Maximum Completion
While firing for 100% in all events and levels you must finish all of the out-post missions, this has to be done prior to start the final story mission. Note:Fight for Chine of Caracas / A.N. On successfully clearing the game you will not be able to start the outpost mission again. Note: it unlocks the factions shop stuff.

How to Unlock Additional Costumes
Finish off the 3rd level bets with your friends at PMC Villa and it will get additional costumes unlocked for your mercenary. If you want great results; bet the optimum amount of cash for initial 2 levels of the challenge. NOTE: Save your game manually and then reload it to make sure you win in the game. Put the least amount of money on your bet in level 3 challenge. To be able to win third level challenge you got to be best.