• Door - Investigate
  
• Winter Iris - Smell
  
• Switch - Turn On Switch
  
• Standing Lamp - Kick
  
• Basket - Wear Basket (This interaction is not necessary to progress, but is part of an achievement.)
  
• Skeleton - Hit
  
• Gun - Pick Up
  
• Door - Put Gun In Keyhole

The hidden item is in the sink. Not sure about when it appears, but I collected it just before I picked up the gun.

This path unlocks Mizuki cured route (meikAI).

• Shoko's Photo - Pull Out
  
• Control Room - Open
  
• Left Bird Cage - Lift
  
• Torn Paper - Piece Together
  
• Panda Ride - Stop
  
• Mizuki - Hug Her

This path unlocks Mizuki traumatized route (keitAI).

• Shoko's Photo - Pull Out
  
• Control Room - Open
  
• Right Bird Cage - Lift
  
• Deflated Balloon - Blow Up
  
• Panda Head - Kick Away
  
• Mizuki - Speak Kindly

The hidden item is lying on one of the benches. Just pass the control booth and you should see it a little bith further ahead.

This path will unlock the rihAI route.

• TV - Hit
  
• Medicine Shelf - Investigate The Bottle
  
• Operating Table - Perform Surgery
  
• Locker - Open
  
• Knife - Throw
  
• Oil Drum - Look Inside
  
• Gun - Shoot

This path will unlock the gumAI route.

• TV - Spin The Dial
  
• Torso - Choke
  
• TV - Turn The Dial
  
• Shelf - Push
  
• Iron Ball - Throw
  
• TV - Turn The Dial
  
• Locker - Open

TIP: Whenever you get a negative TIMIE, spend some time looking around the Somnium for objects which have low time cost interactions and use them there. A choice between 2x10 seconds or 2x30 seconds can make a huge difference in some cases.
If you spent too much time looking around, simply memorise the object and restart the Somnium or the easier way would be to save your game just before you start exploring, then simply load that same save file.
In PSYNCIN' IN THE VaiN a good example would be the Door right behind your starting position. Interaction Open costs only 5 seconds.

This hidden item took the most time to find, but is actually one of the easiest. Instead on interacting with the TV, go past it towards the left corner. It appears once you are close enough.

• Forklift - Drive
  
• Portal A - Put Your Hand In
  
• Warehouse Door F - Go In
  
• Control Panel A - Input Fighting Game Combo
  
• Warehouse Door B - Enter
  
• Warehouse Door D - Open
  
• Warehouse Door D - Enter
  
• Control Panel B - Raise Lever

This hidden item appears after you have cleared a path for Iris with the crane. Once you Enter Warehouse Door B you should see a crane to your right. Walk past is towards the cleat (I believe that's how that metal thing for tying boats is called.), the hidden item is on one of them.

From my understanding there is no one definite way to finish this Somnium. I did three runs and focused on different objects and still managed to clear it. That said the choices you have to make during the interruptions matter, otherwise you waste valuable time.

• Winter Iris - Pick
  
• Phone starts ringing - Ignore
  
• Picture - Fill Out
  
• Ceiling Fan - Blow On
  
• Phone starts ringing again - Ignore
  
• Pot - Wear (This interaction is not necessary to progress, but is part of an achievement.)
  
• Liquid - Stick Hand In
  
• Book (Under the Ceiling Fan) - Tear
  
• Book (On the low table) - Tear
  
• Giant eye appears in the window - Close Curtain
  
• Skull - Throw
  
• Book (On the stereo system) - Tear
  
• Book (On the cupboard) - Tear
  
• Book (A little bit further on one of the shelves) - Tear
  
• Someone starts banging on the door - Lock

The hidden items appears once you've dealt with the giant eye. Once you regain control of Aiba look to the left behind the green barrier, it should be on one of the shelves.

This path unlocks Mizuki's route (syougAI).

• Icy Floor - Lie Down
  
• Oil Drum - Roll
  
• Power Board (Look for it at the far back.) - Throw Something
  
• Ota - Encourage

This path uncloks Ota's route (jikAI).

• Icy Floor - Lie Down
  
• Plate (Closest on the right side) - Breathe On
  
• Forklift - Sortie
  
• Ota - Motivate

The hidden item is behind the green shelves. You'll need to approach the right side forklift, turn right towards the wall and there you should see a small enclosed space between the wall amd the green shelves. Follow along it until you hit a dead end. The hidden item should be right there.

To get Day 4: Iris A just follow the Don't Believe route.

This path unlocks Believe Iris route (irAI).

• Pickaxe - Pick Up
  
• Gate 2 - Dig
  
• Vending Machine - Dig
  
• Crafting Table A - Make Disco Ball
  
• Gate 3 - Dig
  
• Crafting Table B - Craft Monument
  
• Pedestal - Place Monument
  
• Soft Ground - Dig
  
• Debris - Use Love Bomb
  
• Mirror Door - Dance
  
• Iris's Core - Touch Core

This path unlocks Don't Believe Iris route (kenzAI).

• Pickaxe - Pick Up
  
• Gate 2 - Dig
  
• Vending Machine - Dig
  
• Crafting Table A - Make Something Else
  
• Gate 3 - Investigate (You'll get a 1/3 TIMIE, use it on any following interactions that need 60 seconds. If there's a x3 TIMIE instead of the 1/3 one you can alternatively interact with Monitor F and select Listen To Iris, I got a 1/4 TIMIE this way.)
  
• Gate 3 - Dig
  
• ??? - Observe
  
• ??? - Talk (This is also part of an achievement.)
  
• Crafting Table B - Make n/a
  
• Shrine Wall - Dig
  
• Gate (Just follow the street, it's at the end.) - Enter
  
• Mirror Door - Destroy
  
• Iris's Core - Destroy Core (Don't forget to use the 10 second TIMIE. )

This hidden item is quite easy to get, just follow the don't believe Iris route and once you Dig through the Shrine Wall make your way down the street. About halfway through, past the car, you should see a wooden shrine on the right side. The hidden item is inside.

• Egg-Shaped Monument - Place On Pedestal
  
• Chozuya - Investigate (Not necessary to progress, but is related to an achievement.)
  
• Chozuya - Stick Your Hand In It
  
• Pedestal (Peach) B - Take Monument
  
• Pedestal (Peach) A - Place Monument
  
• Egg-Shaped Monument (Blue) - Pick Up
  
• Pedestal (Blue) C - Place Monument
  
• Egg-Shaped Monument (Yellow) - Pick Up
  
• Pedestal (Yellow) - Place Monument
  
• Chozuya - Dig
  
• Iris - Give Fruit Of Immortality

The hidden item appears once you return to the real version of the shrine. I didn't check if it appears immediately once the shrine doors open, but once I made it rain and entered the shrine in place of the seed that we got is the hidden item.

• Sliding Door - Welcome Back!
  
• Phone - My Husband?
  
• Cake - Congratulations, Ota!
  
• Envelope - Let's Do Our Best.
  
• Bucket - Wear (This interaction is not necessary to progress, but is part of an achievement.)
  
• Odoroki-Man Sticker - Chocolate?
  
• Wall Clock - Turn Forward

If you inspect Autograph and select all the options you can get an achievement.


The hidden item appears after you have completely restored the diner, in other words after the correct interaction with the Envelope. It is under the right side table closest to the Odoroki-Man Sticker.

TIP: Since this whole Somnium is very dark and you can't see very well you might find the Map funtion useful here.

• Flower Bud - Worship
  
• Rock 2 - Worship (Not necessary to progress, but you'll need a TIMIE for the very last interacton, otherwise you'll run out of time and won't get Day 5: Hitomi A entry in your album. I was lucky and got 1/4 TIMIE on my first try, but you might need to try other interactions to get at least 1/3 TIMIE before continuing.)
  
• Hole In Tree 1 - Stick Hand In
  
• Hole In Tree 2 - Tackle
  
• Renju - Show Picture
  
• Hole 1 - Jump In
  
• Hole In Tree 3 - Scream
  
• Hole In Tree 3 - Stick Hand In
  
• Hitomi - Show Bracelet
  
• Hole 2 - Jump In
  
• Cluster Amaryllis - Dig Up
  
• Hole 3 - Jump In

This hidden item is fairly easy to find. Once you reach Hole In Tree 1 to the left of it you will see Rock 2, move past it and continue in the same direction. At this point there should be some familiar shimmering in the distance and once you get to it there will be a regular rock and a hidden item peeking from behind it.

• Door 1 - Break Lock With Pick
  
• Door A - Open
  
• Key 1 - Pick Up
  
• Door A - Open
  
• Door B - Open
  
• Door C - Open
  
• Door E - Open
  
• Steel Drum - Push
  
• Door 2 - Open
  
• Door E - Open
  
• Key (08:00) - Pick Up
  
• Door D - Open
  
• Pipe - Kick
  
• Door 3 - Open
  
• Control Panel - Investigate
  
• Control Panel - Insert Key
  
• Control Panel - Rotate Key
  
• Control Panel - Press Switch
  
• Control Panel - Rotate Key
  
• Door D' - Open
  
• Door C' - Open
  
• Door B' - Open
  
• Door F - Kick Open
  
• Ladder (1F) - Tackle
  
• Door 4 - Open

Once you are done with the Control Panel, go through Door D'. Behind your character there should be a bunch of barrels forming the letter L and pointing towards a walkway. That's where you need to go to get the hidden item.

• Stew - Taste
  
• Police ID - Throw it!
  
• Trash Can - Look Closer
  
• Left Speaker - Listen
  
• Adorabbit - Ugly...
  
• Door - Knock
  
• Date's Sofa - Sleep
  
• Date's Coat - Kick
  
• Backpack - This Charm...
  
• Date - Date! (Do this 3 times.)

The hidden item is in the same place as Adorabbit, but in order for it to appear you need to interact with some objects. First you'll have to Lift the Fridge. The option to do so should appear after you interacted with Date's Sofa. Then interact with the Pot which appears right next to the fridge. There will be four options which are all the same, Turn Up... That should get you an achievment. That's it, the hidden item should be on top of the right speaker where Adorabbit used to be.

• Monitor - Check
  
• Monitor - Investigate Knife
  
• Psync Room Door - Move
  
• Psync Machine - Investigate
  
• Psync Gear - Fix
  
• Door - Move
  
• Pool Of Blood - Stick Hand In
  
• Mirror - Investigate
  
• Mirror - Touch
  
• Mirror - Hit
  
• Mirror - Knock Down
  
• You start sinking - %S!nk (Do this 3 Times)

The hidden item appears once you get to the room with the Prototype Psync Machine. It's right next to the Pool Of Blood, hanging from one of the hooks.

Special thanks to Mewdos (the author of 100% Achievement Guide) for allowing me to use some of the images with hidden items. I was too hasty and picked a couple before I managed to take the screenshots.

Also thank you Kurisu ✪, Uguu~ and Jhazat
for help with the Somniums.