Scene 3: Central Hospital
You're now out of your car and in the hospital premises. Walk inside and you'll find that electricity is another factor lacking in this area.
Start exploring the first floor (the square you're in now) to keep track of things, as soon you'll realize that the hospital is vast. Look behind the nurse's station and enter the room. Inside, inspect the panel beside the nurse's call buttons (on the wall) or above what looks like a control room. Its a square panel and will bear the Cafeteria Room key and the Elevator Trunk key (which you will use at the elevator stuck on the 4th floor later.)
To complete the puzzle, just press the MIDDLE panel followed by the SIDES (either which you start but it'd be easier clockwise/counter clockwise).
Once that's done, you can make your way to the 2nd floor of that area. Upstairs, use the CAFETERIA ROOM key in the central room. There's nothing much inside but just walk around until you hear some noise. Look around to find the cans on the left side of the room rolled over. Inspect the can on the right (red) to find a piece of wire. Leave the room and go to the upper left side and enter the room with a blood splatter in front of it. Note that beside the cafeteria, this is the only other room in the floor that's open so don't waste time on the other rooms on the floor since they're busted off from rust.
Inside,you'll find that there's not much to see until you inspect the farthest stall (hidden by the curtain) with a message written in blood. Nothing particular to get here so you can move on to the next floor.
The 3rd floor layout is basically the same as the 2ndflr and only 2 rooms are accessible. The middle room is the DAYROOM. A book on one of the tables reads Emily Dickinson's poem, "I shall not live in vain". Nothing to do here for now. After leaving, continue walking to the lower left side of the area where you'll hear a noise. Enter the room to find dead bodies of cats. Don't forget to inspect the cat and dig in to find a BLOODY key.
NOTE: Usually in the game, whenever you hear something, its inside the room you're in front of or nearby.
Continue on to the last floor. Upstairs, you will notice that green stain in front of a room. If you inspect it, David will say its probably vomit. Note again that where there's stains leading someplace, it means its accesible. Enter inside where you'll find a Silhouette sitting in the chair and disappear instantaneously. Pick up the note on the floor and head outside. Here, make your way to the top left side where the elevator is stuck and get inside. This is where you get to use that ELEVATOR TRUNK key. Get the AED from the trunk and make your way back downstairs.
Coming down, you will hear a noise (3rd flr) of a child. Enter the MIDDLE ROOM where Emily Dickinson's book was and you'll meet up with a lost child that calls himself FLUFFY. As you converse, you will find out all sorts of things about the child before he races outside of the room. No worries, you'll meet him again later as you progress through the game.
Make your way back to the 1st floor and enter the room behind the Nurse's Station. Inspect one of the lockers where you will use the WIRE you got earlier. Inside will be a NOTE WITH A NUMBER. Go outside the room and walk towards the door without power. Just talk to it and David will use the BATTERY from the AED you got from the elevator trunk. Then use the NOTE and enter the code. 
Again to keep track, clear one floor first before heading to another. Enter the STAFF ROOM (the room in front straight ahead) to find the COUNSELING ROOM key (found on 4th flr with elevator,middle room). Take note of the HAMMER on top of the table in the room as you will be needing this later on. Go to the next room (right side) or the DIRECTOR's room and read his diary on the table. You will get the HINT PAPER that you will need to open the chest beside the diary. There is also a LOCKED SAFE on the left side of the room,so take note of it for now.
Don't leave the room yet as a letter piece hides somewhere. Inspect the flower vase in the middle of the room to find the letter Y. Now you can go to the next floor.
On the 2nd floor, enter the PEDIATRICS ROOM (beside the stairs) where you will find Fluffy. A few talks later, he will be tailing you afterwards.
Head to the 3rd floor and check the phone to get the letter F. Enter the MATERNITY & GYNECOLOGY room (2nd room to the right besides the stairs) and take a SMALL KEY from the shelf next to the bed.
Enter the room in front of the one you came from. Its the women's bathroom. Notice the pieces of wall fragments on the floor. Keep this place in mind as you will be using it soon. Once you come out of the bathroom, Fluffy will comment that he needs to use the bathroom and head down to the room opposite the stairs. A few moments later, Fluffy will panic not being able to come out as the door is stuck. David notices this too and startles at the sound of Fluffy's cries. Something is going on inside. Head back to the WOMEN'S BATHROOM (beside the one Fluffy went in) and INSPECT the crack on the wall (this is necessary or you won't be able to get the item needed to break it). Now, remember the HAMMER? Get it. Head downstairs and enter the STAFF ROOM (1st flr) where you can now have a use for it. Run back the bathroom and break the wall. Once inside, open the stall to find Fluffy crying there. Aside from being alone in the dark, he cries to David after seeing a "familiar" figure in the game.
After that's done, you can head back on the previous other part of the hospital (the other side with 4 floors). Return to the 4th floor of the other side and enter the COUNSELING ROOM (middle room).
Now there's TWO silhouettes sitting down the chair. Don't mind them as they mean no harm and can do nothing to you. After they disappear, check the left-most cabinet to read a DIARY. You will get the PSYCHIATRY ROOM key once you're done. Don't forget to check the board to read the NOTE as this will serve as your clue later to open a door on the 3rd flr (other side of the hospital).
Head out of the room and go to the CAFETERIA (2nd flr). Just talk to the teacup to acquire the letter L. Run back down to the room behind the Nurse's Station and inspect the box of LOST & FOUND items to get the letter I piece. Now we have 5 letters in our possession. One more to go. Well, remember that note we found in the board of the Counseling Room? It's the location of the numbers needed for the door lock in the 3rdflr of the other side of the hospital.
Now, run over to the other side of the hospital where there was a telephone. Using the picture, go to the farthest right side of the 2nd floor. There will be a hallway there with rooms that have medical equipment inside.
Following the clue, it points that the first number will be on the middle room of the 2nd floor. Moreso, the code is written somewhere on the bed. Do this right (there will be choices what you need to do) and you'll get the first code which is 7.
Moving on, same area but on the 3rd floor, inspect the trash can of the FIRST room (near the door you came from) and you will get the second number which is 1.
The last number will be found on the board with notes on the 4th floor, farthest room. Again, choose your answers wisely,but don't fret if you don't get it right as there is no consequences whatsoever. Just choose again until you get it right. If you're wondering why the need to go through all the trouble instead of inputting it manually is because the option will not be available unless you physically find the answers on the game. Just enjoy the hunt. The Code will be 716.
Once you're successful, you will find yourself inside the emergency exit stairway. Make your way to the top where the final letter is found and interact with the door. You will have to hault there for a while as the door is covered with WIRE and you have yet to acquire the item to open it.
Despite all that trouble, you will need to retrace back to the 1st floor and get the MEDICINE ROOM key from the locked cabinet in the STAFF ROOM (1st room beside the stairs). Head down the basement where the MEDICINE ROOM is located. As soon as you get down, you will be interrupted by Fluffy's singing of The Crooked Man and David will impart some of his past experience. After that, enter the room next to the stairs. Read the obvious DIARY on the table to learn that Hydrogen Bromide dissolves iron. MAKE SURE THAT YOU HAVE OBSERVED THE FACT THAT THE ROOF DOOR IS SEALED BEFORE ATTEMPTING TO FIND THE CHEMICAL. Otherwise you will not be able to pick it up. Find the chemical inside the room on the farthest shelf to the left. Once you get your hands on it, return upstairs (3rdflr) and open the rooftop door.
You will be shown another set of conversation between Fluffy & David. Once that's done, look around to find an old newspaper littering the area. Its not an item you pick up, but rather fills in some of the question in the story. To find the final piece, get up the top balcony of the rooftop stairs. Just interact with the side stairs from where you came from and you'll see the shining M piece on the top. Get back down and make your way to the 3rd floor.
As you head your way back, you will hear a noise in the 3rd floor. You might want to save for a while here as you will be facing the crooked man again. This time, you can find him inside the MATERNAL & GYNECOLOGY room, second room to the right from the stairs. Once you come in, you will find him eating the fetus display. Some scenes will ensue and the crooked man will go after FLUFFY here instead of chasing after you. David will be knocked on the wall and the game will ensue with him bearing an injury (HP 50). Walk out of the room and go upstairs. Note the fire extinguisher by the side of the stairs as you will be using this soon.
Continue walking the hallway where you'll find the monster cornering Fluffy. After the dialogues, you will be timed a total of 1min (plenty of time) to grab the FIRE EXTINGUISHER you passed by earlier (again,by the side of the stairs). The story will continue as David makes the crooked man back off with his strength.
Moving on, after that is over, head back stairs to the 1st floor. Enter the DIRECTOR'S ROOM where you have now completed collecting the missing pieces. To open the chest, make out the word FAMILY from the letters you collected. If you read the notes on the side cabinet (right side near the door) you would have guessed it right. Well, no matter. You will get a SAFE KEY. Look no further and use it IMMEDIATELY (as some gamers claim to have gone out without using it) on the black safe inside the room (left side). It will give you a very useful weapon: the REVOLVER & PISTOL AMMO. What do you need it for? To fight that monster again.
To meet the crooked man, head out and make your way back to the rooftop (go to 3rdflr,right farthest corridor,to the hallway out to emergency stairs). You might want to SAVE your progress here before entering the rooftop door as this part will be somewhat hard. After doing so, open the door to find the crooked man scaring Fluffy (that is one messed up monster).
The Game Battle will ensue and you will be killing the crooked man using the revolver. Clicking the left mouse cursor will make him shoot so be WARNED. If you hit Fluffy, the game will end. You can point the gun whichever direction David faces. It will be quite difficult as they both will be moving a lot but as you play you will notice that he's following the kid so make the best of this opportunity. I think it will take a good 5-10 shots for him to die (wasn't counting).
BOSS STRATEGY: Fluffy is following you, the monster is following Fluffy and mostly ignores David. You can try to get in between them and shoot till you're content. You can also lead Fluffy far away from the monster and then shoot him in the back. Whichever strategy works for you, just avoid hitting the kid.
After killing and filling him with holes and then throwing him off the rooftop ("Oh God,please die already!"), some story-telling time.
Finally! With the monster gone, you can now get out of this Hospital. Use the front entrance (where you came in) to get out. But before you could, David stops in his track. He is deffered by noises.
No need to look around. Just walk your way back to the Clinic side of the Hospital (where the Director's Room is) and down to the Basement (the one that looks like a Morgue). You will notice that the room beside the MEDICINE ROOM is now open. Just enter the room and watch the rest of the story unfold.