The Red Sea/guide

Bat (バット)
Enter the top yellow door. Interact with the bat beside the door.

Uniform (制服)
Step on the orb. Go south-east and enter the cracked door. Go right into the next hallway. Go down the dark hall and interact with the third door. Interact with the coat stand.

Eyepatch (包帯と眼帯)
Interact with the needle. Go north-east and go between the two horizontal rows of needles. Go north and step on the puddle of blood.

Blood (血)
Step on the orb. Head up and go under the crooked purple arrow. Go north-east and interact with the bloody paper scrap. A cutscene will play and you'll get the effect afterwards.

Futon (布団)
Sleep in the bed in Nagi's dream bedroom.

Needle (針)
Interact with the needle. Go north-west and interact with the bloody needle. Go north-east (avoiding the chasers) and step into the middle of the triangle-shaped row of needles. Go north and interact with the bloody hand.

Normal End
Collect all the effects. Wake up and leave the bedroom. Go right and enter the door beside the one you came out of.

In this ending, [Nagi will discover the corpse of the blue-haired NPC that appears in his dreams and begin to cry ]. The screen will then fade to credits and a thank you message.

True End
Collect all the effects. Return to the Nexus. Equip the Bat Effect and enter the top yellow door.

In this ending, [The screen fades to black and several whacking sounds will occur. The screen will fade back to the NPC dead and Nagi covered in blood. ]. The credits and a thank you message appear afterwards.