Hobbies And Interests
Sis
You will encounter your first boss during the mission "Assault the Yacht" of "Operation Blood Feud." Purchase several fire bombs from the clearinghouse to prepare for this mission. Once the fight begins, lob a fire bomb near where she is hiding to get rid of her shields and seriously damage her health. Take cover and wait for her to fire at you. Once she stops to reload, toss another fire bomb at her. This may kill her outright. If she survives the second bomb, rush her and deliver a few kicks and punches to finish her off.
Brayko
You will encounter Brayko during the "Assault Brayko's Mansion" mission. Before you take on this mission, complete enough other missions to meet Steven Heck in Taipei and purchase the spiked cocaine. Make sure to buy this and bring it on this mission. During the fight, Brayko will occasionally stop to take cocaine and if you brought the spiked cocaine along he will receive damage every time he does so. When he does, however, steer clear. He will pull out a knife and go on a rampage that can devastate your health. Try to stay as far from Brayko as you can, and aim for his head whenever possible. You will need to find cover as much as you can, as Brayko's sub-machine guns can do a lot of damage. If you brought the spiked cocaine it is only a matter of time before he kills himself, so your primary goal is to just survive until this happens. Take shots whenever you have the opportunity, but do not take any risks to do so.
Darcy
The "Greybox: Full Circle" mission is the final mission of the game and has a couple of unique boss fights. The first is with Darcy. Darcy will not confront you directly. He will stay in his tower and attempt to snipe at you or throw grenades from a distance. There are two main ways to take Darcy down. The first is to immediately shoot out the fuel tank in front of you and then hide behind the boxes. Edge over to the side of the boxes and line up your shot at Darcy's tower. Shoot at his head whenever he sticks it out. This method can take a while.
The other method requires taking an EMP on the mission. Climb the other tower in the area with the ladder inside. Use your EMP on the locked door at the top. Inside the room is a sniper rifle that will make taking Darcy down a snap.
Leland/Westridge
Depending on what you do in the final mission, the last boss of the game will be either Leland or Westridge. They use slightly different weaponry, but you defeat them in the same way. The high ground is key for this fight. Run to the highest level as soon as you can. Drop a few bombs down on the fuel tanks to take out the guards and then concentrate your fire on Leland/Westridge. You should be able to take him out without ever taking a hit from him.