One Night Walkthrough

A few people have been getting hopelessly stuck in my latest game One Night, so I have opened an official walkthrough thread for you to consult and post your questions about the gameplay in.
This walkthrough will get you from the start of the game to the finish, but be careful as it does not reveal the locations of: Save Rooms
Enemies
Supplies

New to Build 5.1: You can access hidden game modes by entering certain codes as your name.

EASYMODE - Allows you to begin with a handful supplies in your inventory. There will also be less monsters.
HARDMODE - Allows you to play a harder version of the game where there are more monsters and Defense Items cannot be found.
NEWDIGS - Unlocks an alternate outfit for the player character.
MOREFEAR - Enables jump scares, which appear at random locations in the game.

The Prison

• Upon starting, immediately take the Rope off of the floor. Next, examine the open crate and the door out of the room will open.
• Walk down the corridor, following the sounds you hear, and then, when you are ready to proceed, return to the beggining of the corridor and open the first door on the right.
• Pass through the room into the kitchen, where you can find a Pickaxe lying on the floor.
• Return back to the corridor, and at the next door you come to, use the Pickaxe to break inside. Read the journal on the desk, then proceed to the hole in the corner of the room, where you can use the Rope to climb down.
• In the dug out room, cross over to the small chest and enter 38 to open it, obtaining the Prison Key from inside.
• Return back to the main corridor, and the remaining two doors can be opened with the key. The key will also unlock the exit.
• When you arrive outdoors, head west, and follow the path around the prison entrance to find a ladder shaft. Climb down it and retrieve the Keycard from the open crate, then climb back up again, then quickly head south, into the small stone building with the open door, bringing you to an office.
• Read the maintenance report on the desk, then proceed through the room and in the warden's office read the letter on the desk and search the drawer in the room's corner for a Gate Key.
• Return to the previous room and unlock the pipe storage with the key, and break off the Iron Pipe.
• Leave the building and head east, coming to a large concrete building. You can use the Iron Pipe to wedge the door open.

The Main Building

• First, go through the door on the right hand side behind the counter.
• This will lead you into the file room eventually. In here, you can read the finance report on the computer desk and then cross to the top right hand bookshelf and push it aside*, revealing a hole.
• In the room beyond the hole, you will find a Main Building Key hidden away. Return to the initial lobby and this time enter the door on the left.
• *The shelf can only be moved if you have read the maintenance report.
• Cross down the corridor, and enter into the locker room, which is the third door on the north side. All of the others are locked for now.
• In the locker room, you can save and read the memo, which will tell you how to solve the puzzle to obtain the locker code.
• To obtain the locker code, return to the file room and examine the shelves. Each one is numbered, and has a date listing. Note the shelf numbers and enter them into the locker's combination lock in order of the dates, earliest, to latest. A Desk Key is inside the locker.
• Return to the corridor outside, and enter the first door on the north side, which you'll need to unlock with the Main Building Key first.
• In the single office, unlock the desk and retrieve the Power Conduit from within. A cut scene will ensue.
• After you regain control, return to the corridor and you'll notice that the second door on the north side is now unblocked, so unlock it with the Main Building key and enter, then enter the first room on the right.
• Read the handwritten note and search the open crate for a bottle of MHL-3 Base.
• Leave the room and follow the corridor, entering the pharmacy through the last accessible door you find. In here, you must mix the MHL-3 Base with other chemicals to make it into an acid.
• Chemistry is hard at the best of times, and this time your life is on the line. Either follow the directions in the Chemistry Book or pour 144 litres, 99 litres and then 207 litres to create the MHL-3 Compound. Place this into the synthesis machine for 360 seconds and you'll have mixed the MHL-3 Acid. Remember that there is some left over for later if you need it.
• Return to the store room and use the MHL-3 Acid to burn open the steel crate, obtaining the Explosive found inside.
• Leave the Main Building, and return to the dug out room in the prison. Use the Explosive to blow apart the debris.

The Underground

• Proceed through the dug out corridor, going downstairs, until you emerge in the lower coridor. This is a large, ring shaped room with many doors leading off of it.
• Going clockwise around the room, enter the fourth door you come to, into the security room, where you can read the scientist's notes which are on the desk, and obtain the Underground Key from the drawer in the top left hand corner of the room.
• Return to the coridor outside and unlock the second door after the one you emerged from with the Underground Key.
• Inside the second cell block, there is a corpse holding a Startup Disk in it's hands. Take it and leave the room.
• Proceed to the next door you find and unlock it, then enter. Read the orders on the desk to recieve a clue on how to solve the puzzle lock on the locker.
• The clue is written in code. The code is thus: the first two letters of each word are normal, but the rest are accelerated by one, thus "hemmp" would be "hello". Once you have figured out what the message reads, it will be easy to unlock the locker and achieve the Power Conduit contained within. Once you have it, leave the room.
• Enter the next door, the one which leads into the center of the room, and obtain the third and final Power Conduit from the drawer within. Now, using the Underground Key, unlock the power room (the second door clockwise from the entrance) where a cut scene will take place.
• After the scene, place all three Power Conduits into the module in the center of the room, returning the power to The Complex.
• Return to the server room in the main building, where the mainframe will be waiting to be turned on. Insert the Startup Disk and enter the code of 0707 to put The Complex's computer systems back online.
• Now you will be able top open the final door in the west corridor, which leads into the south corridor. Unlock the side armory, the first door on the east side of the coridor with the Keycard and obtain the Empty Handgun inside.
• Proceed to the end of the south corridor into the lobby. Take the Empty Bottle from the table and read the scientific book out of which an Entrance Key will fall. Use this key to unlock the exit and go outside.

The Laboratory

• Go southwest after leaving the main building and enter the large metallic building you come to.
• Cross through the clearance room into the lab core, and unlock the first door on the north side with the Keycard and enter. Inside you will find a corpse brandishing a Level 2 Keycard for you to take.
• Exit back out to the core and unlock and enter the door directly opposite the one you emerged from, the calibration room.
• In this room, read the handwritten note on the table to obtain the codes to the four terminals. The codes are encrypted so you must encrypt them first. The codes are written as letters, but switch those letters for their numeric counterparts and you will have the numeric codes. Zeroes are already decoded, and of course, the number at the beggining of eack code tells you which terminal to enter it into.
• Enter the codes to calibrate the laboratory equipment, then leave, back into the core, and then back into the clearance room, and finally, out of the laboratory itself.
• Return to the main building now, but do not enter. Instead, follow the path around it to the east, unlocking the first door you see with the Level 2 Keycard which leads into the main armory.
• The main armory's storage room is locked, but read the keeper's journal on the desk to see a clue to figure out the code to unlock it. (If you don't know Prime Numbers, the code is 136.)
• Inside the storage area, collect the Ammunition and leave. Now return to the prison from earlier, but on the way, as you pass through the main building, stop past the pharmacy and collect some of the acid you made earlier in the Empty Bottle to obtain some more MHL-3 Acid.
• Return to the underground area under the prison, where two final doors await unlocking with the Level 2 Keycard. One door will lead into the maximum security block, at the far end of which awaits a Laboratory Key in an open crate.
• The other door leads into the solitary confinement room, which is unlocked. Read the guard's diary and then enter the word Clouds into the terminal to unlock the cell, inside of which you will find a second Laboratory Key.
• Once you have the two keys and some MHL-3 Acid, you must return to the laboratory core, and enter the second door on the north side of the corridor.
• Load the Handgun with the Ammunition and use it to blow open the gasolene soaked gate. Beyond the gate will be a control panel you can use to unlock the experiment room.
• Return to the core and enter the final door on the north side, the huge experiment room. Cross through it and unlock the door at the far end with the Laboratory Keys, and enter the archive room.
• Use the MHL-3 Acid to burn open the locker and take the Plasma Cannon stored within, then return to the experiment room. A huge cutscene will ensue, and you will face the first of the game's two boss fights. Simply run around, dodging the enemy's attacks until the Plasma Cannon charges, upon which, run into the enemy to deal damage. Do this three times to defeat him.
• In another cut scene, you will recieve the Admin's Keycard.
• After you regain control, leave the laboratory entirely and return to the path that leads eastward around the main building. Unlock the final door you come to at the end of the path, and then enter the door immediately to the south.
• Use the Admin's Keycard to access the computer terminal, and choose to access the latest update news. Read the update post carefully, and note all the numbers that have numbers half their value on either side, for example 242, you would note 4.
• Return to the terminal's main menu and enter the numbers you noted as a password, and you will activate the charge of the Atomic Destabilizers, which you can remove from the locker to the right after you unlock it with the Admin's Keycard.
• Once you have them, return to the experiment room in the laboratory, and after the cutscene, step into the teleporter.

The Other Side Of The Merge

• As soon as you regain control, take the Crystal from the glowing sculpture and leave the room.
• Follow the chasm, and enter into the first door you find, into the shrine area, where you must read and note the carved obelisk before continuing to the end of the chasm, into the ritual grounds.
• Head south through this area, and enter the door at the far eastern part, which leads into a small antechamber containing a second Crystal, which you must take with you.
• Then, enter the southern door into the statue room, and immediately proceed to the small ruins containing the five statues. Place the two Crystals into the Dragon and the Alechemist statues, then head south through the area, where you can pull a lever to unlock the exit.
• Choose the fork to the right and continue down to the end of the path. In the right atrium, plant and activate a Atomic Destabilizer then return to the core, and this time, choose the left fork.
• A cutscene will now roll, and the final boss fight begins! Defeat the boss using the same method used for the previous boss.
• Once you have defeated the boss, sit back and enjoy the ending and feel happy that you have survived One Night

The End