Overdrive (オーバードライブ)/guide

Roller Skates
(You must have the weapon effects)

Kill the NPCs to earn 1000 yen → go to the Town → Shoes Shop → interact with the shop keeper then interact with the present.

Laser Gun
Go to the Aquarium World → enter the Purple Gate → Purple World → interact with the white floating stone.

Maid
Go to the Ghostly World → enter the White Gate → Moss Passage → left, right, right, center, center, center, left, right → Brickwall World → Blue Door → Mansion → 2nd floor 4th door → interact with the stand with maid dress.

Detective
Go to the Ghostly World → enter the White Gate → Moss Passage → left, right, right, center, center, center, left, right → Brickwall World → interact with the shadow behind one of the brickwalls.

Spear
Go to the Snow World → interact with the red flower → Forest World → go up 3 rows and find a house → Doctor's Room → interact with the spear.

Crescent
Go to the Aquarium World → enter the Orange Gate → Cosmos World → top, right ,right, bottom → interact with the crescent moon.

Saxophone
Go to the Town → School → 2nd floor center door → interact with the saxophone.

Heart
Go to the Town → School → 3rd floor right door → interact with the Hell Block → Yellow Hell → enter the Building entrance → Laboratory Entrance → Laboratory Hallway → find the papers with number in the rooms → go to the bottom exit → enter the password (Hint: the shapes of the papers) → interact with the heart in the capsule.

Cyber
Go to the Town → School → 3rd floor right door → interact with the Hell Block → Yellow Hell → enter the Building entrance → Laboratory Entrance → Laboratory Hallway → room on bottom left → interact with the monitor → Cyber World → interact with the flashing block.

Robot
Go to the Ghostly World → interact with the gray gear → Gear World → enter the building → enter the door on the left → interact with the robot.

Paper
Go to the Snow World → step on the small lake → Under Water → walk between the white statues → enter the entrance on the left → interact with the glass bottle on the left.

Robin
Go to the Snow World → interact with the red flower → Forest World → go down 2 rows and interact with the withered tree → Withered Tree World → interact with the robin.

Shadow
Go to the Aquarium World → enter the Orange Gate → Cosmos World → top, bottom → interact with the black star → Chromatic World → climb down the hole → Red Cord World → wait until the place change → interact with the shadows that sit on the bench.

323's Endings Guide
After collected all concepts, the cage on the bottom of nexus will appear a glow that leads you to the Concept Room, drop all the concepts to the monitor.

End2
Leave the room and go through the way.

End3
[Follow the Paper concept's guide then enter the entrance near the bottle to the Angel Place, use weapon to attack the angel for 5 times then interact the center to obtain the box key (if you have Detective effect you can find the hint), then back to the room and interact with the box beside the capsule to obtain the secret key, leave the room and use it to the locked door then interact with the UFO. ]

Unlock 543
[Go to Cosmos World → top, bottom → interact with the black star → Chromatic World → enter the block entrance → Hospital → go to the right hallway → last room → interact the center to obtain the key (if you have Detective effect you can find the hint) → go to the left hallway → go to the end → enter the room → interact with 543. ]

After that, 323's room will appear a present box, interact with it will switch to play as 543.

Sheath Knife
Sleep on the dream bed repeatedly → Lucid Dream → interact with the sheath knife on the floor.

Pigeon
Go to the Flower Field → interact with the red flower → Forest World → go along the same row and find the pigeon.

Doctor
Go to the Purple Bridge World → enter an entrance → Sky World → interact with the Hell Block → Blue Hell → enter the Building Entrance → Hospital → go to the right hallway → first room → interact with the shadow NPC that wears doctor coat.

Virus
Go to the Purple Bridge World → enter an entrance → Sky World → interact with the Hell Block → Blue Hell → enter the Building Entrance → Hospital → go to the right hallway → second room → interact with the monitor → Cyber World → interact with the purple color virus.