Instructions
Go to Indy's office. You must place five hidden chests on a green pad in the middle of the room.
Switch to any girl character and use her extended vertical jump to reach the top shelf in the back of the room. Grab the first chest and bring it to the green pad.
Switch to any academic character and use his translation ability to obtain the chest with hieroglyphics. Take this chest to the green pad.
Blow up the dishes on the left side of the level with explosives, then switch to a digger character and use his shovel to unearth the chest below. Take this to the green pad.
Blow up the glass on the right side of the level using explosives. Inside is the fourth chest. Place it with the others on the green pad.
Select a Thuggee character and pray in front of the statue in the room. A secret panel will open. Switch to a small character and head inside to grab the last chest.
Build any object on the green pad using LEGO bricks, then switch to Indy and destroy the object with your whip. A key will appear; collect this and take it to the artifact room.
Grab the blue jewel from the floor of the artifact room and place it on the pedestal. This will reveal a set of gears with a keyhole. Use your key to get them started.
Go back through all 18 levels of the main game and collect 10 treasures in each level. For each level, you'll receive an artifact, which will appear in the artifact room. Once you've collected all 18 artifacts, the Warehouse level will open.