In Level 1, don't bother looking for the battery in the same place as you did
in the demo. It's not there :) -- it's hidden much better now. After you kill
the guys in the shack with all the radios, go thru the door and keep walking.
You will come to a junkyard full of dogs. In the back of the junk yard there
are 2 stacks of cars that are short, the battery is hidden in the trunk of
the one that isn't on fire.
In Level 2, you need to get the key from the desk in the room with the safe,
talk to Louie, and turn off the power. Then, to get into the safe, you'll
need to hire some help. Go to the bar and approach the fat guy and press
positive. He'll then offer to blow the safe for 50 dollars. If you can't
figure out how to get him to open it, remember the command key ('Q' by
default) and the activate key ('F' by default). Point to the fat guy, hit
'Q', then point at the safe and hit 'F'. Then get out!
On the level, "Pier Pressure", where you go down to the docks to help Big
Willie get revenge. In the part after you kill everyone on the loading dock
(with all the crates) and on the ship (with 2 doors, one is called SECURITY,
the other is locked [gives the "locked" sound when you try to open it]).
Kill everyone around, and search all the bodies, but the 2nd door (not
the SECURITY one) will not open until you kill the thug up on the railing
of the ship. Some people have had problems with the door not opening even
after doing so. This may be a bug in the game or the scripted sequence.
If you think it's stuck, use the noclip cheat to walk through the door.
At the Steel Mill, rescue David from the office, and be careful not to shoot
him when you do (he's the guy not packing a piece). Then get the key from the
bartender and go find out that Moker isn't in his office. Leave the office by
the other door (not the one you entered), and then walk to the dead end and
shoot the barrels on the bridge above you to get out.
In the Train Wreck area, go down into the sewer and keep an eye out for a
ladder going up, about half-way down the sewer. Up there you'll see two wheel
valves -- one of them (the one marked East 55) will turn, so turn it. This will open
the door at the end of the tunnel.
SECRET: On the map Lizzie's Problem in Episode 3, The Wharf, jump in the
water and swim around until you find a fat man with a pair of concrete shoes
on. Take out your crowbar and beat him until he becomes fish food and pick up
the key he leaves behind; the key will open a previously locked door and for
your efforts you will be rewarded with some serious fire power and some hard
cold cash. Hope you remember which door you couldn't ever open . . .