copied and pasted:
Here are some tips i figured out while playing the game on professional. I will perhaps edit this article so it's worth looking several times if you have problems:
If you managed "Separate Ways" with Ada its recommended to use Ashleys armor outfit. As mentioned, nothing can harm her and she can be used as a distraction. Another good tactic is letting the villagers/sect members/soldiers pick her up. Because of the heavy armor, they fell down and you can kill them easily with your knife. If there is a group with more infected, let one pick Ashley up and shoot anonther one into the knee followed by a kick. If you're lucky, you will knock out others. If you don't, just try it again. You can save a lot of ammo and health with this method, but you may need to practice it a bit.
Furthermore, if you have problems solving the end of chapter 2-2: I advise you to upgrade the Shotgun, Red9 and the TMP as good as you can at first. After the cutscene, immediately barricade yourself and pick up everything (even go upstairs and collect the grenades and herb). position yourself in front of the first step and wait for the infected to break through the barricade into the house. Use your shotgun and keep the villagers away from you. If there are 2 or more Las Plagas growing (that will definitely happen) watch out for Luis to help you or use a flashgrenade to eliminate them at once.Try to collect ammo and herbs but dont leave your spot for more than a few seconds. After Luis is telling you to move upstairs, run quickly into the right corner (there is a closet near by and 2 windows) and continue to get rid of the infected (burn them with your grenade(s) if there are two many of them in front of you). If you have a few seconds to breath deeply, knock over the ladders behind and besides you. This will make sure that you cannot be attacked from behind. Continue to kill the infected coming from the opposite side and keep in mind that the ladders are positioned again very fast on professional. If necessary, knock them down again. Don't lose your cool and keep in mind that chapter is almost done.
Note: It's doable with 2 first-aid sprays and 1 complete herb mixture (you can even find all 3 sorts of herbs inside of the cabin). Good luck!
I just found out something which might be new for some of you: Right after chapter 2-2 you are able to choose a path: The left one leads you to the Bella sisters while the right path is concluding an El Gigante. It's very important that Ashley has her armor for this tactic, otherwise it won't work. Choose the part with El Gigante and shoot the chains off the first door before El Gigante appears. After the Cutscene, stop him with the huge rock above you and then run immediately into the second cabin. Take the key and run to the door to escape. Right after this, return and run together with ashley to the area in front of the cabins. Give her the "wait" command and step behins her. El Gigante will be busy with grabbing Ashley. This is you chance: Collect everything you can find (Don't forget the treasure above you and you will find lots of ammo in this section!) After Ashley rescued herself just give the "follow me" command and run to the door again and escape. If necessary, repeat this until you got everything you want. With this tactic, you don't need to fight El Gigante but you're able to collect every item in this section.
Fighting the Red Gaitling-Gun Guy to get the gallery key: in the early section of the castle you will head to a room where 2 archers, 2 sect members with golden masks and 1 red member are standing on a plattform above you. If you don't have the automatic rifle yet, buy it from the merchant. Proceed until you are on the second floor of the hall. It's almost impossible to kill the red guy before he will run through the door so don't get nervous if he does. Kill all of the other infected and jump down at the end of the floor. The door will open and the red guy tries to run to the gaitling gun which is located in the middle of that room beneath you. This is your chance: He will stop and you're able to shoot him with your rifle. After the first shot he runs away again. If you're a good shooter you can kill him right before he's entering the door which leads him downstairs but it's not easy to manage it here. If you didnt' get the job done yet, you will have another chance to kill him. Run after him and after opening the door, a infected with a wooden shield is trying to attack you. Don't pay any attention to him and concentrate on the red guy again. Pick up your shotgun and shoot him right into the knees. He will fall to the ground and you can finish him off getting the gallery key before he's able to attack you with the huge gaitling-gun.
Another tricky situation might be purchasing the grail of the king. After you picked it up, 3 knights will appear and attack you. Run away and shoot them with your shotgun. After the las plagas are visible, throw a flash grenade and they will die at once. Repeat that with the coming black knights again and you can save lots of health and ammo again in this section.
Fighting the two El Gigantes: It's highly recommended to get rid of one El Gigante while pushing the trigger very early. He will fall into the lava and you just have to worry about the remaining one. Run to the ladder and climb it. Wait until El Gigante is very close and jump off! He will start to shake the scaffold and you can attack him with your shotgun or even with your knife (this will last longer but it is very effective). Climb the ladder and jump off again until he starts to shake the scaffold again. Repeat this several times and El Gigante will be gone without taking damage!
Fighting U3: In Chapter 5-2 you have the pleasure to face that huge monster called U3. During the first part of the confrontation while you're in the container, don't shoot it because you can't kill it there. Push the buttons at the right time to avoid U3's attacks. If you can't run away, throw a flashgrenade and focus on the buttons to escape that section as soon as possible. Now it comes to the real fight: Choose your magnum and shoot it several times (Use the fire barrels too!). After a few shoots, it starts to dig and trys to attack you from beneath. Just push the buttons and wait for U3 to show again. Shoot again with your magnum or TMP, if you don't want to waste too much magnum ammo here (Keep in mind to keep a good distance while using the TMP). It will soon be gone.
Note: If you have enough space left in your briefcase, buy a rocket launcher and beat U3s ass even faster!
Fighting Jack Krauser: Well guys, if you made it this far it comes to a very frustrating and hard battle with Jack Krauser. In the first part, you have to collect 2 pieces for the main door. I recommend to use your knife and your TMP to get rid of Jack Krauser. If he's close to you, knife him and if he has a certain amount of distance, switch to your TMP. After he disappeared, collect everything you can find. Repeat this until you face him at the top of the tower. Krauer on professional is very annoying and very offensive so be careful all the time because he can kill you quickly even with full health. The Rocket Launcher will not help you because you can only damage but not kill him with it. Use your magum (fire power fully upgraded!) and your knife to take him out. If he's close to you (that will happen almost al the time) knife him and while he's on his knees, shoot him with your magnum in the head. Be careful and stay alert because you have to do a lot of fast button smashing too in this battle. If you feel crampled, run away and wait for the right moment to shoot him in the knee. If he's doing his jumping attack, you can hit him even several times with your magnum. Don't worry about the time, 2 minutes are very little time, but if you fight offense and thought out, you can get rid of him in 40-50 seconds. After he's gone, collect everything you can find (if you have enough time of course) and get through the door to finish this hard chapter.
The final chapter: After i defeated Krauser, i thought it will be easy to get to Saddler because Mike will help you through this huge section with lots of soldiers with his helicopter. Unfortunately, this isn't the case. Of course he will help you but you have to to the work almost by yourself, because Mike needs very very long to take out the machine guns. On normal, he kills almost everyone but on professional it's up to you to move to Saddler step my step. The semi-auto rifle and patience is the key to success here. Kill the archers and rocket launcher guys with your rifle from a good distance and watch out for the soldiers on the ground. In the first section you can use the ladder to your advantage but i recommend to run away because you can be surrounded very easily. After the section you have to climb several ladders (right before J.J), the game will save. After you died, you can return to the previous section and collect every item. Surprisingly, there are no soldiers anymore. Head back and get rid of the soldiers coming down the steps before taking care of J.J. Use your rifle here to shoot him in the head to kill him quickly. After you opened the door, the game will save again. The next and last section can be very frustrating because there are a lots of soldiers coming from everywhere and even 3 machine guns!. Immediately turn left and climb up the ladder. A guy with a wooden shield will appear soon, so make sure to kill him very quickly. Now focus on the ladder and kill the soldiers, who try to climb the ladder. Unfortunately it isn't as easy as it sounds, because another soldier with dynamite will appear right in front of you. Kill him quickly with your shotgun and continute knifing the soldiers who climb the ladder from beneath. After you killed all of them, catch a breath and focus on the first machine gun on the left. Pick your rifle and shoot him in the head while he needs to reload (you have very little time to kill him). (If you're lucky, Mike will take care of the machine gun guy on the right, but don't bet on that). If he doesn't it's up to you. There is still one machine gun guy on the right and one beneath you so run as fast as you can to the house next to the machine gun guy. He cannot attack you here, so just use your TMP. From this part, kill the rocket launcher guy too who's standing on the opposite site of you. Reload and heal yourself if necessary and run back and climb down the ladder (Beware of soldiers who may appeared again). Run back to the entrance and move left. Hide until the last machine gun guy needs to reload and run quickly to the elevator (on the ground where you can find the green herb too). Choose your rifle again and wait for your chance to take him out with a headshot (Same tactic as mentioned before). After you get the job done, collect everything, pulling the 2 switches and go through the door to finsih the last difficult part of the game.
Fighting Saddler: The final boss of the game isn't even half as hard as Krauser was so don't get nervous. If you have a rocket launcher, you can beat him within seconds. After the fight has begun, shoot the eyes on his legs and wait for him to show his huge eye. Pick your rocket launcher and shoot him. He's not dead yet, so run away to the next platform. Ada will throw another rocket launcher to you, finish him off and you've beaten the game on professional!
Note: If you don't have a rocket launcher, use your TMP and magnum to kill him. Shoot his eyes on the leg and shoot with the magnum on his huge eye. If you don't have any mangum ammo left, you can push the buttons and Leon will knife him automatically. Repeat this several times (use the fire barrels too!) until Ada is throwing the rocket launcher. Continue as mentioned above.
Video credit: xxxDerVxxx.