Dev known as Rio was kicked out of the development team due to evidence of grooming and pedophilia towards a 13 year old boy who lasted for 3 years until it was made recent, Yuga and RagnaEdge knew of this behavior and did nothing to stop it. Here is the evidence: https://drive.google.com/file/d/1_BtvntUrTem8m_V8H73yBipY04HjpccE/view
Kura Puzzles are unlocked the same way Wallpapers are, and in most cases, they are linked: always check your wallpapers after encountering characters or triggering events mentioned below. Here is a list of all 67 puzzles you can currently unlock. You can press Shift for a hint.
#0- Automatically obtained when you start Yume 2kki.
#1- After visiting Urotsuki's Dream Scene in Flying Fish World.
#2 - Painter-kun's Painting - Interact with Painter-kun in the Art Gallery.
#3 - Sign - When you first enter Sign World from the Bug Maze.
#4 - Green Juice - Interact with Aojiru ("Cripple-Tan") at the Hospital.
#5 - Three ┏（∵）┛ - When you first enter the Bowling Pin World from Bowling Zone.
#6 - Square - Wake up after your money is at least 800.
#7 - もっきゅっ！ - After interacting with the Monmons in the Marijuana Goddess World at least 6 times in one visit.
#8 - Grinning Eyes - After you go up the ladder to Tapir-San's Place.
#9 - Blue People - Unlock Wallpaper #74.
#10 - In Vain - After getting 20 effects (including the instructions).
#11 - Insect - When you get the Bug effect.
#12 - Hakoko & Megusuri Uri - Interact with Hakoko at the Eyeball Shop.
#13 - Darkness - After interacting with Desu-chan and Onee-chan, then visiting the Lower Highway.
#14 - Pipe Organ - Interact with the Black Beret Twin in the Dark Room.
#15 - Director's House - Unlock Wallpapers #64, #85, and #88.
#16 - Octopus - When you use the Fairy effect on Tako Otoko in Atlantis.
#17 - Bane-kun - When you unlock Wallpaper #36 after getting the Spring effect.
#18 - Odoriko-san - Interact with Odorika in Red Streetlight World (you don't need the Maiko effect).
#19 - Gakuran - Interact with Gakuran-kun.
#20 - Stardust - When you enter Space from Tapir-San's Place.
#21 - Rune Mark - When you first enter Theatre World.
#22 - Primitive Present - When you first enter the Tribe Settlement.
#23 - Little Red Riding Hood & Apple - When you get the Red Riding Hood effect.
#24 - The Grudge - Cutting the rope at the well in Fairy Tale Woods and getting captured.
#25 - Hanging Child - When you encounter Koshukei-tan in Graffiti Maze.
#26 - Are You Going Again? - Interact with Megusuri Uri outside his shop in Visine World.
#27 - The Playing Is... - Interact with the clown that plays the accordion at the Underwater Amusement Park.
#28 - Mask - When you chainsaw Painter-kun in the Art Gallery.
#29 - Penguin - When you get the Penguin effect.
#30 - Black Witch - After chainsawing the sane Shadow Woman in Forest World, going underground and then emerging.
#31 - Eyeball Human - When you encounter the Eyeball People in the Spelling Room.
#32 - Urotsuki_RT - When you get the Chainsaw effect.
#33 - Smile - When you first enter Guts World.
#34 - End - When you pass by the meteor along Highway (near the tunnel).
#35 - Would You Like To Dream? - After you go to sleep 30 times.
#36 - Elf - When you get the Fairy effect.
#37 - Candy Girl - When you use the Cake effect on Sweets Musume in Cutlery World.
#38 - Tear - When you chainsaw a stick person in the Penguin Game.
#39 - May I Eat? - When you use the Cake effect on Sweets Musume in Cutlery World.
#40 - My Name - When you spell "Urotsuki" in the Spelling Room.
#41 - Bug - When entering Seishonen's room when it's glitched.
#42 - RPG-7_Untitled - When you manage to escape the room after getting surrounded by chasers in Urotsuki's Dream Apartments.
#43 - Uro & T-Shirt-kun - Interact with the blue NPC at the end of the Arrow Maze.
#44 - Room Window - When you go through the black window in the Never-Ending Hallway.
#45 - Each World - When you go through all of the Nexus portals.
#46 - NULL MI - After looking up at the ceiling of the inescapable room in Binary World's tower.
#47 - Idenshideau - After meeting the fish in the jar in Green Binary World.
#48 - ぜんまいの鶏 - When you kill the angel priest in Fountain World
#49 - ジェイ子 - When you are chainsawed by the hockey mask girl in GALAXY Town
#50 - 暗彩光を飛ぶ - Automatically obtained when you start Yume 2kki.
#51 - Coffee Urotsuki - When you have a cup of coffee at the cafe in the Eyeball Archives.
#52 - 退水の先に - When you approach the pink structure in the Polluted Swamp
#53 - Within the Cage - When you find the caged Shadow Bird in the Halloween Forest part of the Cat Cemetery.
#54 - Nigella - After sleeping one time.
#55 - 揺蕩うくじら - When you enter Paradise for the first time.
#56 - When you get a ticket from the ticket dispenser in the Overgrown Condominium's arcade room.
#57 - After entering the head with the smiling creature in Head World.
Removed/Modified Kura Puzzles
#50 - 暗彩光を飛ぶ - Old version of KP#50 modified in version 0.113, unlocked by meeting "It Came From Behind" in Neon City.