There are 20 achievements:

• 15 for story progression
  
• 1 for collecting one collectible
  
• 4 for clearing enemy sequences within a time limit

The latter five can obviously be missed if you aren't careful. The four for clearing enemy sequences within a time limit are especially easy to miss if you aren't careful, so keep an eye out for the four purple achievements below.

The game only saves at manual save points. There is only one save slot per play through and there are no checkpoints. All enemies in the game are instant death on contact, and every time you die you are sent back to your latest save. I don't say it much in the guide, but remember to save frequently.
Though this can be useful if you are too slow for the four time-limited achievements.

These are the game's collectibles. Collecting one unlocks a model for the gallery. Only one is required for achievements, but there are actually 21 gallery items in total. I've listed the locations for 19 coins in my guide, and I wasn't able to find the last two coins. If anyone knows where they can be found, tell me and I'll add it in.

Every QTE in the game is passed with the spacebar. You can just spam the key when I mention that a QTE is coming in the guide.

A Long Night Ahead
Get out of your car.
• Walk forward, through the gap in the gate and up to the front door. It's locked.
  
• Look left, pick up the very obviously highlighted Azada in the distance.
  
• Run back across the front yard towards the massive tree and crawl under a root.
  
• Use the Azada to break the boards blocking the doors and enter.

• Follow the linear path down.
  
• After passing "a map of the country drawn in blood", there is a save point on the right before entering the next room.
  
• In the next room, don't crouch through the hole in the corner yet.
  
• Look on the desk and take a Mirror Shard.
  
  Paint The Town Red

  Acquire Bloodlight.
• Solve the puzzle by the door.
  
• Turn on bloodlight and pick up the Sun Emblem on the crates.
  
• Return to the "a map of the country drawn in blood" and pick up the Country Emblem.
  
  
• Enter the door by the puzzle to a prison area.
  
• Inside the cell next to where you entered is the Body Emblem.
  
• Approach the corpse in the centre of the room and take the Cell Key (Copper) from its eye.
  
• Turn right, use the Cell Key (Copper) to unlock the middle cell.
  
• Pick up Cell Key (Iron) inside.
  
• Unlock the row of cells at the back with the Cell Key (Iron).
  
• Crawl past the guy banging his head on the wall and pick up Cell Key (Lead).
  
• Unlock the single cell on the side of the room we haven't explored yet with Cell Key (Lead).
  
• Take the Bronze Key from the body.
  
  
• Enter the crawlspace I told you to ignore earlier.
  
• Crawl inside and slowly approach the enemy.
  
• Once it spots you, exit back to the main room and retreat to the save room.
  
• When comes out, crawl back inside and pick up the Gallery Coin (1) and Death Emblem.
  
  Pay-Per-View

  Obtain first gallery coin.
• Exit through the locked door opposite the crawlspace with the Bronze Key.
  
• Go downstairs, look at the stone tablet with bloodlight. Place the four emblems into the slots on the door in order: Death, Country, Sun, Body.
  
  
• You enter a chapel.
  
• Pick up the Rusty Knife stabbed into the bloody mound on the left.
  
• Enter the door with a cross on the right.
  
  
• See a save point.
  
• Continue forward to be introduced to the Pasatsat.
  
  Risen

  Encounter the Pasatsat.
• To defeat it, you need to trigger traps scattered around the room when it's in the trap's range.
  
• Trigger all four traps within two minutes for an achievement.
  
  • Immediately run forward to the lever on the pillar and drop the sandbag on it.
    
  • Turn left and to see a lever on the floor. This activates the floor spikes directly in front of it.
    
  • While it’s stunned run to the opposite end of the room to another lever on a pillar. This drops the cage on the ceiling.
    
  • Lastly, run to the corner with the beds to find the last lever. This triggers an arrow trap that shoots horizontally across the room.
  Master Torturer

  Defeat the Dambuhalang Pasatsat within 2 minutes.
• With the Pasatsat gone, enter the small rooms by floor spike trap and search the drawers for the Torturer's Key.
  
• Another room has the Sampaguita Crest.
  
• Unlock door at the back of the room with the Torturer's Key.
  
  Pain Is An Understatement

  Defeat the Dambuhalang Pasatsat.
  
  
• You enter a library area.
  
• There's a Gallery Coin (2) in the enclosed area on the right when you enter.
  
• There's a save point further in.
  
• Next to the save point is where the crests should be placed, but you are missing two.
  
• Don't open the closet behind the bookshelves by the double doors unless you want an instant-death QTE.
  
• Upstairs are some letters you can read as well as the second Sampaguita Crest.
  
  
• Return to where you entered to find Skull 1 down some stairs on a barrel as well as a set of double doors leading to the next enemy: Madre Superiora.
  
  Tainted

  Enter the Crypt.
• Turn on bloodlight to see a path marked on the floor. You must walk on this path or you will die.
  
• This puzzle is a word chain of sorts. The first skull you picked up has symbol that looks like an uppercase "I", so use it on the skull at the back that begins with the same symbol.
  
• Continue the pattern for the remaining skulls around the room, ending with the Priest Skull in the enemy's lap.
  
• Save and return to the chapel.
  
  
• At the back of the chapel on the right side is Gallery Coin (3) by the four candles.
  
• Place the Priest Skull on the altar, which activates the two statues by the skull door.
  
• To unlock the skull door, you must rotate the statues based on the paths highlighted on the door.
  
• Face the statue the direction the path is going. When the path goes down face the statue towards you, and opposite when the path goes up.
  
  • Left statue: right, left, right, left, right, right, left
    
  • Right statue: left, left, right, right, left, right, left
• Before opening the door, note five ropes on the walls that hold up a chandelier above the skull. Two are near where we first entered, one on the left wall near a pew leaning against a wall, and two in the corners nearest the skull. They aren't highlighted now, but will be in the following sequence.
  
• Upon opening the door, Paring Pugot will chase you around the room.
  
• You must cut the five ropes I mention earlier to drop the chandelier on the skull. Start with the two furthest from the skull and go clockwise around the room ending at the one by the skull door.
  
• Cut all five ropes and destroy the skull within two minutes for an achievement.
  
  Skull Crusher

  Defeat the Paring Pugot within 2 minutes.
• Now you can open the skull door safely.
  
• Pick up the Mess Hall Key from the closet, a Mirror Shard from the desk, and a Gallery Coin (4) in the drawer.
  
• Return to the library.
  
  
• Unlock the double doors behind the bookshelves with the Mess Hall Key.
  
• The last table in the mess hall has a Gallery Coin (5).
  
• Also pick up the Mirror Shard from the shelf and the final Sampaguita Crest.
  
• Return to the library, and place three crests in their correct slots.
  
• Open the hidden door. This is the last chance to explore the beginning area.
  
• Follow the narrow passage until a cutscene plays. The two enemies are right on your tail, so sprint though the passage jumping and crouching past obstacles. Hit the lever at the end to kill them.
  
  Out Of The Frying Pan...

  Reach the first floor of the mansion.

• Look around. Pick up the Lapis Lazuli on the sofa. In an opened drawer in the corner is Gallery Coin (6).
  
• Under the stairs in the corner find a mechanism and use the Lapis Lazuli on it.
  
• Go upstairs.
  
  
• The doors leading to the West Wing behind you are locked.
  
• Follow the corridor to a set of double doors. These are locked too, but beside them is a save point. This is only save point left in the game, come here to save often.
  
  
• Having saved, return downstairs the way you came and enter the door beside the stairs.
  
  Eater Of The Dead

  Encounter the Bal-bal.
• See three statues as well as three massive picture frames.
  
• Take the Painting of a Preacher from the middle frame.
  
• Take a Gallery Coin (7) from one of the small desks.
  
• Crawl through to the next room.
  
• Keep crawling to avoid attracting the Bal-Bal's attention. Take the Painting of a Caring Mother from a bed.
  
• There is another Gallery Coin (8) on a bookshelf.
  
• Sneak behind the monster into the bathroom, and take the Painting of a Martyr.
  
• Sneak back to the first room and place:
  
  • Painting of a Caring Mother in the middle frame
    
  • Painting of a Martyr in the left frame
    
  • Painting of a Preacher in the right frame
• Pick up the Mirror Shard that appears.
  
  
• Go back upstairs.
  
• Continue along the corridor and down the stairs at the other side.
  
  
• Down here, search the drawers to find a Ruby.
  
• Enter the door near the ruby and pick up the Topaz on the bookshelf.
  
• Further in the room is an enemy, the Busaw. It won't chase you as long as you don't get too close.
  
  Flesh Eaters

  Encounter the Busaw.
• Near the Busaw is a Gallery Coin (9) on a drawer.
  
• Above the drawers is a mechanism with a book symbol that you can use the Ruby on.
  
• Exit the room and use the Topaz on a similar mechanism with a crown symbol.
  
• Enter the doors in the opposite corner to the drawers with the ruby.
  
  
• You can read a note in a nearby opened drawer.
  
• Further in is a clock we can't solve just yet.
  
• Enter the door beside the clock.
  
• Find a note in here with three times underlined: 09:00, 07:05 and 15:15.
  
• Deeper in the room is a bookcase with a puzzle. Rearrange the books so the times are: 09:00 (sun), 03:15 (moon), 07:05 (sun).
  
• Input these three times into the clock earlier. The clock will show a sun symbol when used with normal light and a moon symbol when used with bloodlight.
  
• Pick up the Blue Book that drops.
  
• Use the Blue Book on the bookshelf with the arrow (it's in the other room; use bloodlight to see it) and move it aside to reveal a hidden passage.
  
• Don't drop into the cellars, we'll return here last since this place is buggy.
  
• Return upstairs and save.

• Nothing's changed up here, most of the doors are still locked. Enter the door in the corner near the east stairs.
  
• Proceed through the room into the next.
  
• When you walk near the symbol on the wall, a monster will chase you. Ignore everything and run to the back of the room by the double doors for a QTE when the monster reaches you.
  
• After it's dead pick up the Mirror Shard nearby and Diamond on the bust.
  
• Enter the double doors.
  
• Before reaching the corner in the corridor, the monster will start chasing you again. Quickly run down the corridor to the end, pick up the Bedroom Key on a stack of books and use it to unlock the door next to you.
  
• Enter and quickly close the door behind you.
  
• In the bedroom, use the Diamond on the mechanism with the necklace symbol.
  
• Enter the next room and find a note on a small table, a Gallery Coin (10) on a chair, the Westwing Key on the desk, a Mirror Shard and mirror on the bedside table at the back.
  
  • Note: the mirror doesn't appear in your inventory, but will be used automatically when needed.
• Exit and return the way you came.
  
  Agony And Tragedy

  Explore Maria's room.
• On your way back out, in the corridor where you were chased is a Gallery Coin (11) on a sofa.
  
• Return, save and unlock the West Wing door. Be careful while upstairs now, enemies will occasionally spawn that can catch you off guard.
  
  
• The first door is locked; we'll be back here later.
  
• Continue down the corridor and see a Gallery Coin (12) on a table on your right.
  
• When you reach two doors, enter the one on your left and continue through the rooms to an Emerald.
  
• At the end of the corridor, enter the bathroom on the right to find a Gallery Coin (13).
  
• Return the way we came and a scene will play with a mysterious woman.
  
  Lady Of Mystery

  Encounter Corazon.
• Save first before following her into the room in the corner.
  
  
• In the bedroom is a Gallery Coin (14) on a sofa.
  
• Examine the picture.
  
• Approach the Batibat to begin the next enemy sequence.
  
  Sleep Paralysis

  Enter your nightmare.
• You are trapped in a maze. You start in a hub room with three doors, each with a portal behind them. Each portal leads to rooms with more portals.
  
• Starting from each of the portals in the hub room, you need to go from portal to portal to find three bells. Going into the wrong portal will send you back to the hub room.
  
• There's an achievement for ringing all three bells and escaping within five minutes. Time is pretty tight, so it may be better to solve this once first before reloading and rushing through it.
  
  • Starting from the portal on the floor:
    
    • Turn around, follow the corridor to the end and through the portal. Be careful of the monster here, you can't waste too much time.
      
    • Follow the narrow corridor to the end.
      
    • Turn right, follow corridor to end.
      
    • Enter the portal beside the bar.
      
    • In a room with three portals, enter the middle one.
      
    • The bell is in this room. Ring it and take the nearest portal to go back to the hub room.
  • Starting from the portal through the regular door:
    
    • Through the portal besides the barrels and crates.
      
    • Through the portal at the far end.
      
    • In a room with three portals, enter the left one.
      
    • Follow the corridor to the end and into a portal.
      
    • The bell is in this room. Ring it and take the nearest portal to go back to the hub room.
  • Starting from the portal that's up the drawer stairs:
    
    • Through the portal besides the barrels and crates.
      
    • Jump over the display case into the next room and go through the portal at the other end.
      
    • Follow the left wall to a portal.
      
    • Turn around and through the portal at the end.
      
    • Turn left, through the right portal.
      
    • Turn right, down the corridor to the stairs. Follow this corridor to a portal.
      
    • The bell is in this narrow corridor.
  • After ringing the third bell, quickly go through the nearest portal to return to the hub room.
    
  • A new portal has appeared on the bed, go through it to return to reality.
  Sweet Dreams

  Break the Batibat's curse within 5 minutes.
• Pick up the Master's Bedroom Key on the bed.
  
• Save, and unlock the door in the opposite corner from the west wing door with the Master's Bedroom Key.
  
  
• Examine the note on the dresser to begin the next enemy sequence.
  
• You must gather five necklace pieces and rebuild the necklace within a certain time limit.
  
• Complete it in under a minute for an achievement.
  
• The five pieces are located:
  
  • Necklace Strap: On a chair near a dresser in the corner
    
  • Necklace Tooth: On the table at the foot of the bed
    
  • Necklace Pendant: On the windowsill
    
  • Necklace Rat Skull: On top of a drawer in the corner
    
  • Necklace Pearl Jewel: In the wardrobe in the far corner
• With the five pieces in hand, return to the dresser near the entrance and place the pieces according to the silhouette.
  
  Immune To Fear

  Break the Mambabarang's curse within a minute.
• Pick up the Mirror Shard on the bed.
  
  
• Return to the room in the corner by the eastern stairs.
  
• Use the Emerald on the mechanism here with the feather symbol.

• Return downstairs via the eastern stairs.
  
• The mosaic should be complete now, so open it and pick up the Mirror Shard and Bar Key behind it.
  
• Unlock the door left of the mosaic with the Bar Key.
  
  
• Explore the room to find a Mirror Shard on the smaller counter.
  
• Jump over the counter to a Gallery Coin (15).
  
• Enter the double doors.
  
  
• Walk down the stairs to enter a flashback(?) scene.
  
• Run past the crowds of people picking up a Gallery Coin (16) and a Mirror Shard at the end.
  
• Return upstairs and enter the door in the corner.
  
• In this eating area, take the stake from the skeleton hanging on the wall.
  
  • Note: Like the mirror, the stake won't appear in your inventory.
• Go to the small room behind it to find a Mirror Shard.
  
  
• We should have everything now, except the stuff in the cellar.
  
• Save and down into the cellar.
  
• There's a Gallery Coin (17) on a table here.
  
• Opposite the coin is a doorway with the Penitent and inside.
  
  Eternal Attonement

  Encounter the Penitent.
• This enemy is extremely buggy. I think you're supposed to lure it out and then sneak back in to take the shard, but on my play through it was chasing me around the room and then just bugged out when I turned off my flashlight. You can also try luring it to under the stairs in the other room. I checked other people's play throughs on YouTube and the same thing happens to them (some bug out on the barrels) so I don't know how to do this properly. (See: #1 #2 #3 #4 #5.)
  
• Either way, get the Mirror Shard and head back upstairs.

• With twelve shards in hand, you can finally go through the double doors by the save point.
  
• This is the final boss fight and it sucks.
  
• At the beginning, the woman will offer you a nice drink. You can take it or leave it, you get a slightly different ending scene depending on your choice.
  
  
• In the boss' first phase, you need to extinguish the three candles around the room and then stab it with the stake you picked up earlier.
  
  • Press F on the keyboard to holster the torch and equip the stake. You can keep the torch holstered the entire battle since it's not needed.
    
  • While the candles are lit, the boss will chase you around the room.
    
  • Once the three candles are out, it stays completely still until you stab it.
    
  • The cycle repeats.
    
  • After three stabs the next phase begins.
• For the second phase, run around the room picking up all thirteen mirror shards on the floor while the boss chases you.
  
  • The shards are picked up simply by running over them.
    
  • The shards have tiny hitboxes so picking them up can be annoying.
• Stab the boss one final time to end the battle.
  
• Leave the room.
  
  Revelation

  Get all 13 mirror shards.
  
  
• So the entire place is on fire now, follow the corridor.
  
• Before going downstairs, there's a Gallery Coin (18) on the railing.
  
• After going downstairs, there's on more Gallery Coin (19) on a drawer before exiting out the front door.
  
  Escaped!

  Escape the burning mansion.
  
  
• Back outside, the crazy woman will attack you in an escape cutscene. Keep spamming that spacebar and pass two more instant-death QTEs to finally get the ending.
  
  The Inevitable

  Encounter the Manananggal.