1.Once Upon A Time In Bid Wars Theme Park
On the wall close to the stairs in front of your room

2.Invitation
Under the HELLO Sign

3.2001 Space Bids
In the door which you need pick up the lock

4.Close Encounters Of The Crappy Kind
the most hard one for me, searched 4 hours.
In the gate of theme park, break the grass board on your right.
It's behind the container.

5.Brand New World
Go behind the board.

6.Guardians Of The System
In the left of the Auntie Mary's Auctions area, on the wall of the house.

7.How The Island Was Won
Go through the middle of Red Barn and the tower.

8.Dino Stranding
On the second floor of the Knuckle's Party

9.The Two Body Problem
In the Summer Camp area, right of the carousel.

10.Top Secret Mikko Lavatory
In the Summer Camp area, Left of the carousel.

11.Mikkong
In the Spirits' Cave, On the dining car.

12.Mikko Avengers
On the top of the mountain, in the hot dog shop.

13.Jurassic Mikko Cavalry
In the River Rock Mine. On the wall of the left room.

14-18 In the Throwback Theater, you won't miss it
Bar Moth
They Came From Cosmos
Natural Born Cleaner
Mikko's The Meaning Of Life
Mikko Things To Come