All the answers here! The main goal in 100 Doors is to escape the room. Using all the possibilities of the device you need to open each of 100 doors and move the doors to the next Level.
Search for hidden objects, solve puzzles and use an items to do this!
Grab the stick on the bottom right. Grab the axehead on the left of the door. Assemble them in your inventory.
Use the axe to shop the tree of your left.