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 42613 ) → 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 computer → Cyber World → interact with the flashing block.

Robot
Go to the Ghostly World → interact with the gray gear → Gear World → interact with the spanner.

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.