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!
Tap on the closet to open it and take the towel.
Use the towel to wash the steam on the window of the door.
Use a mirror to see the code correctly.