Head right and talk to the Gift Shop Clerk with Square/Y and as you walk away he should ask you to bring three trinkets and drop the Novelty-Sized Key . Grab the key and head left to unlock the “Employees Only” Door.
Drop down to the Broken Old Well and spot your first hidden Cave Painting . While we cannot get it this second, unless you have the time traveler, we will get it in a bit.
In order to pass the door on your left, you’ll need to pull the Lever in the basement, by the door, and on the other side of the door. Once open, it will stay open for good and you can freely move your characters around. Take whoever has the Crowbar and continue left and jump up the platforms just before the Bell to reach another Cave Painting and the Old Well . Pry the Rusty Crank off it and take the crank back to the Broken Old Well and use it to get the Bucket .
This will also break the well and allow you to collect the Cave Painting you saw previously.
Return to the Old Well and continue up to the Fuse Box and place the bucket on top in order to grab the Fuse. Now, return to the basement with the vending machines and place it in the Empty Fuse Box . The New Grog Machine will pop out a Can of Grog that your characters can drink, but what you want is the Hot Dog from the Hot Dog Machine.
Grab the Hot Dog and return to the bell and throw it on the Pit of Spikes.
Witnessed a hot dog cooked with the monster's breath.
Switch characters and grab the Fuse and return it to where you got it from. You should now have one character by the bell and one up by the Levers and Such. You need to ring the bell with one character and then switch and use the levers to move the dog-like creature out of your way. Proceed down the new tunnel, grabbing the Cave Painting , and then drop into the water below.
Your other character will automatically move up to you when you reach a new checkpoint, so there is no need to worry about them.
Climb out of the water to your right and head down the ladders to the Box of Dynamite and grab a stick. Now head back up the ladder and light the Dynamite via the Flame and rush over to the right and toss it by hitting O/B by the rocks. Continue down the tunnel and hop up the first ledge to grab the first Trinket and then switch characters.
Follow the path and go down and through the water to find the second Trinket and then return to the fork and go up to stand on a weighted platform to open the door. Switch to you final character not holding an item and walk through the door. Take the first ladder you see to grab the third, and final, Trinket and then head down and use the Elevator Call Button further down the tunnel. Press it again and quickly hop on to return to the start of the tunnel and take all three items to the Gift Shop Owner.
Before heading into the tunnel, check the Postcard Display and grab the Postcard that pops out. Now, talk to the owner and head inside the cave with the Postcard to get the trophy/achievement Shoplifting .
Saw a postcard stolen from the Gift Shop.
Follow the cave into the next pool of water and then jump on the rope to pull down the counterweight. Switch characters and jump across the gap, now open with the weight pulled up, and hop to the other side where a Cave Painting is.
Continue to the right and remove the character from the rope so you can pull the box left, just between the gap above. The fall is normally too far for your characters, but with the box now in place they can carefully fall to safety. Move all three characters on the weighted floor lever and continue.