Mafia II

Are you having a hard time (like me) killing Derek and his companions inside the warehouse? Here is an really easy way to do it.

Kill all the enemy's in front of the warehouse. Do not enter the warehouse. Take your car, that should be parked in front of the warehouse, and drive it into the water nearby.
Don't worry you won't die. Go back to the warehouse and you will notice that the lower warehouse door is locked, but instead Derek's office door is now open. Even on "Hard" you can kill Derek and his companions without to much effort by taking cover inside his office.

I've heard of a few people who have had problems with getting Joe to follow them through this mission. You start off at the top of a skyscraper, and you have to work your way down. You will get to a point where someone throws a molotov, setting fire to a door you need to get through. Joe then says to jump over a table that is in front of a window to the next part. When I played the mission, Joe refused to come down the stairs until Vito was at the bottom, and he walked up to the table, and was jumping at it, but was unable to perform the "vault over" animation, and I had to complete the mission alone - possible, but difficult.

On my second playthrough, I found that crouching in front of exactly where he stands causes his vaulting animation to work. The only problem is that you must follow him immediately, putting yourself in the line of fire. This is fine on Easy and Normal, but a pain on Hard.

If you follow this method, then you should be able to complete the mission with Joe following you.

(I used to have a better version of this solution, but I could not recover it following the Great Server Crash of September 2010)

If you are having issues with the mission glitching at the end when you are paying back Bruno, you need the restart the mission and when once you kill Derek, and take the money, you then need to ""ONLY"" Crush cars for the extra cash! Do not try to rob any stores it will for some reason cause you to glitch out and the Chapter will never end.. I was having this same issues until i tired this and it worked. I hope this helps anyone who has this issue.

Not missable

Chapter 14: Stairway to Heaven

Never Forget

You'll have orders to take out an old Mafia rat. You'll be given a special high-powered car for this job. Don't wreck it, or your mission could instantly fail. Drive and let Joe do the shooting as always.

Even after killing the target, you'll be assaulted by federal agents. Lose them as quickly as possible, taking long winding roads and other tricky ways to keep them off your tail. After getting a good ways away, head to the way point to drop off Joe. Since youre still wanted change your clothes and grab a new set of wheels. Your next destination is the docks.

Dock Work

Derek wants you to teach the dock workers a lesson, however they will share with you a distressing story. Your priorities will change: kill Derek and Steven, ending the dock madness.

Your shotgun actually has fairly good range. The dockworkers will provide some help with killing off Steve outside the ware house. However, you'll be on your own once inside. You can actually drive your car into the building, and while it won't be too useful offensively, it can provide some much needed cover. Derek will throw down explosives while his guards attempt to shoot you down. Take them out one by one before moving to the top. Derek isn't any tougher than the average goon, so kill him with a few good gunshots.

With Derek dead, raid his safe. He'll have barely enough to pay off your debt to the loan shark. If you need some extra cash, rob gun shops to a big payoff.

Skyscrapping By

Even with enough to pay your dues, you'll need Joe's other half. Follow the trail of waypoints and scenes to learn that he was taken to the Mona Lisa bar. Head there and you'll be escorted to half built skyscraper

Arm yourself and kill the three guards with sneak attacks. You'll now need to descend to make your escape. Let Joe take point as much as possible. Once the Vinci mobsters notice you, it will be an allout gun fight.

Even during the hectic fighting, there are collectables hidden around the building. Take the time to grab some. However, the main thing you'll want to pick up is the enemy's guns. a good shotgun will go a long way at destroying your enemy.

Towards the bottom will be a stockpile of grenades. Pick them up and be ready to use them as you enter the lobby. Enemies will come from all sides. Take out the ones that come up the stairs to the left first, and then sweep right to execute the renaming enemies. Some of the mobsters will even be under you, so you'll need to come out of cover to get a good shot at them.

Take a car and bring Joe to El Greco for some healing. With all of the money collected, return to the laon shark and pay off your debt, ending the chapter.

Source: http://www.gamespot.com/features/6274410/p-15.html